Bump the actions group with 2 updates

Bumps the actions group with 2 updates: [actions/checkout](https://github.com/actions/checkout) and [actions/setup-python](https://github.com/actions/setup-python).


Updates `actions/checkout` from 4 to 7
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v4...v7)

Updates `actions/setup-python` from 5 to 7
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v5...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: actions/setup-python
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

.dockerignore

@@ -0,0 +1,4 @@
+.git
+.ruff_cache
+.pytest_cache
+__pycache__

.github/FUNDING.yml

@@ -0,0 +1,7 @@
+github: kevinveenbirkenbach
+
+patreon: kevinveenbirkenbach
+
+buy_me_a_coffee: kevinveenbirkenbach
+
+custom: https://s.veen.world/paypaldonate

.github/dependabot.yml

@@ -0,0 +1,21 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    groups:
+      actions:
+        patterns:
+          - "*"
+
+  - package-ecosystem: docker
+    directories:
+      - "/tests/e2e"
+    schedule:
+      interval: weekly
+
+  - package-ecosystem: pip
+    directory: /
+    schedule:
+      interval: weekly

.github/workflows/ci.yml

@@ -0,0 +1,80 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  test-and-lint:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Set up Python
+        uses: actions/setup-python@v7
+        with:
+          python-version: "3.12"
+          cache: "pip"
+
+      - name: Install package and tooling
+        shell: bash
+        run: |
+          set -euo pipefail
+          python -m pip install --upgrade pip
+          python -m pip install -e .
+          python -m pip install ruff
+
+      - name: Ruff (lint)
+        shell: bash
+        run: |
+          set -euo pipefail
+          ruff check .
+
+      - name: Ruff (format check)
+        shell: bash
+        run: |
+          set -euo pipefail
+          ruff format --check .
+
+      - name: Unit tests
+        shell: bash
+        run: |
+          set -euo pipefail
+          make test-unit
+
+      - name: Integration tests
+        shell: bash
+        run: |
+          set -euo pipefail
+          make test-integration
+
+  docs:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Markdown and mermaid lint
+        shell: bash
+        run: |
+          set -euo pipefail
+          make lint-docs
+
+  e2e:
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: End-to-end tests in a container
+        shell: bash
+        run: |
+          set -euo pipefail
+          make test-e2e

.github/workflows/codeql.yml

@@ -0,0 +1,43 @@
+name: CodeQL
+
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: "27 4 * * 1"
+
+jobs:
+  analyze:
+    name: Check security
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+
+    permissions:
+      security-events: write
+      packages: read
+      contents: read
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - language: actions
+            build-mode: none
+          - language: python
+            build-mode: none
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v7
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v4
+        with:
+          languages: ${{ matrix.language }}
+          build-mode: ${{ matrix.build-mode }}
+          queries: security-extended,security-and-quality
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v4
+        with:
+          category: "/language:${{ matrix.language }}"

.gitignore

@@ -0,0 +1,8 @@
+__pycache__/
+*.py[cod]
+*.egg-info/
+build/
+dist/
+.pytest_cache/
+.ruff_cache/
+.mypy_cache/

.markdownlint-cli2.jsonc

@@ -0,0 +1,13 @@
+{
+  "config": {
+    "default": true,
+    "MD013": false,
+    "MD033": false,
+    "MD041": false
+  },
+  "ignores": [
+    "node_modules",
+    ".agents",
+    ".claude"
+  ]
+}

CHANGELOG.md

@@ -0,0 +1,6 @@
+# Changelog
+
+## [1.0.0] - 2026-08-14
+
+Official Release🥳
+

LICENSE

@@ -1,661 +0,0 @@
-                    GNU AFFERO GENERAL PUBLIC LICENSE
-                       Version 3, 19 November 2007
-
- Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-                            Preamble
-
-  The GNU Affero General Public License is a free, copyleft license for
-software and other kinds of works, specifically designed to ensure
-cooperation with the community in the case of network server software.
-
-  The licenses for most software and other practical works are designed
-to take away your freedom to share and change the works.  By contrast,
-our General Public Licenses are intended to guarantee your freedom to
-share and change all versions of a program--to make sure it remains free
-software for all its users.
-
-  When we speak of free software, we are referring to freedom, not
-price.  Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-them if you wish), that you receive source code or can get it if you
-want it, that you can change the software or use pieces of it in new
-free programs, and that you know you can do these things.
-
-  Developers that use our General Public Licenses protect your rights
-with two steps: (1) assert copyright on the software, and (2) offer
-you this License which gives you legal permission to copy, distribute
-and/or modify the software.
-
-  A secondary benefit of defending all users' freedom is that
-improvements made in alternate versions of the program, if they
-receive widespread use, become available for other developers to
-incorporate.  Many developers of free software are heartened and
-encouraged by the resulting cooperation.  However, in the case of
-software used on network servers, this result may fail to come about.
-The GNU General Public License permits making a modified version and
-letting the public access it on a server without ever releasing its
-source code to the public.
-
-  The GNU Affero General Public License is designed specifically to
-ensure that, in such cases, the modified source code becomes available
-to the community.  It requires the operator of a network server to
-provide the source code of the modified version running there to the
-users of that server.  Therefore, public use of a modified version, on
-a publicly accessible server, gives the public access to the source
-code of the modified version.
-
-  An older license, called the Affero General Public License and
-published by Affero, was designed to accomplish similar goals.  This is
-a different license, not a version of the Affero GPL, but Affero has
-released a new version of the Affero GPL which permits relicensing under
-this license.
-
-  The precise terms and conditions for copying, distribution and
-modification follow.
-
-                       TERMS AND CONDITIONS
-
-  0. Definitions.
-
-  "This License" refers to version 3 of the GNU Affero General Public License.
-
-  "Copyright" also means copyright-like laws that apply to other kinds of
-works, such as semiconductor masks.
-
-  "The Program" refers to any copyrightable work licensed under this
-License.  Each licensee is addressed as "you".  "Licensees" and
-"recipients" may be individuals or organizations.
-
-  To "modify" a work means to copy from or adapt all or part of the work
-in a fashion requiring copyright permission, other than the making of an
-exact copy.  The resulting work is called a "modified version" of the
-earlier work or a work "based on" the earlier work.
-
-  A "covered work" means either the unmodified Program or a work based
-on the Program.
-
-  To "propagate" a work means to do anything with it that, without
-permission, would make you directly or secondarily liable for
-infringement under applicable copyright law, except executing it on a
-computer or modifying a private copy.  Propagation includes copying,
-distribution (with or without modification), making available to the
-public, and in some countries other activities as well.
-
-  To "convey" a work means any kind of propagation that enables other
-parties to make or receive copies.  Mere interaction with a user through
-a computer network, with no transfer of a copy, is not conveying.
-
-  An interactive user interface displays "Appropriate Legal Notices"
-to the extent that it includes a convenient and prominently visible
-feature that (1) displays an appropriate copyright notice, and (2)
-tells the user that there is no warranty for the work (except to the
-extent that warranties are provided), that licensees may convey the
-work under this License, and how to view a copy of this License.  If
-the interface presents a list of user commands or options, such as a
-menu, a prominent item in the list meets this criterion.
-
-  1. Source Code.
-
-  The "source code" for a work means the preferred form of the work
-for making modifications to it.  "Object code" means any non-source
-form of a work.
-
-  A "Standard Interface" means an interface that either is an official
-standard defined by a recognized standards body, or, in the case of
-interfaces specified for a particular programming language, one that
-is widely used among developers working in that language.
-
-  The "System Libraries" of an executable work include anything, other
-than the work as a whole, that (a) is included in the normal form of
-packaging a Major Component, but which is not part of that Major
-Component, and (b) serves only to enable use of the work with that
-Major Component, or to implement a Standard Interface for which an
-implementation is available to the public in source code form.  A
-"Major Component", in this context, means a major essential component
-(kernel, window system, and so on) of the specific operating system
-(if any) on which the executable work runs, or a compiler used to
-produce the work, or an object code interpreter used to run it.
-
-  The "Corresponding Source" for a work in object code form means all
-the source code needed to generate, install, and (for an executable
-work) run the object code and to modify the work, including scripts to
-control those activities.  However, it does not include the work's
-System Libraries, or general-purpose tools or generally available free
-programs which are used unmodified in performing those activities but
-which are not part of the work.  For example, Corresponding Source
-includes interface definition files associated with source files for
-the work, and the source code for shared libraries and dynamically
-linked subprograms that the work is specifically designed to require,
-such as by intimate data communication or control flow between those
-subprograms and other parts of the work.
-
-  The Corresponding Source need not include anything that users
-can regenerate automatically from other parts of the Corresponding
-Source.
-
-  The Corresponding Source for a work in source code form is that
-same work.
-
-  2. Basic Permissions.
-
-  All rights granted under this License are granted for the term of
-copyright on the Program, and are irrevocable provided the stated
-conditions are met.  This License explicitly affirms your unlimited
-permission to run the unmodified Program.  The output from running a
-covered work is covered by this License only if the output, given its
-content, constitutes a covered work.  This License acknowledges your
-rights of fair use or other equivalent, as provided by copyright law.
-
-  You may make, run and propagate covered works that you do not
-convey, without conditions so long as your license otherwise remains
-in force.  You may convey covered works to others for the sole purpose
-of having them make modifications exclusively for you, or provide you
-with facilities for running those works, provided that you comply with
-the terms of this License in conveying all material for which you do
-not control copyright.  Those thus making or running the covered works
-for you must do so exclusively on your behalf, under your direction
-and control, on terms that prohibit them from making any copies of
-your copyrighted material outside their relationship with you.
-
-  Conveying under any other circumstances is permitted solely under
-the conditions stated below.  Sublicensing is not allowed; section 10
-makes it unnecessary.
-
-  3. Protecting Users' Legal Rights From Anti-Circumvention Law.
-
-  No covered work shall be deemed part of an effective technological
-measure under any applicable law fulfilling obligations under article
-11 of the WIPO copyright treaty adopted on 20 December 1996, or
-similar laws prohibiting or restricting circumvention of such
-measures.
-
-  When you convey a covered work, you waive any legal power to forbid
-circumvention of technological measures to the extent such circumvention
-is effected by exercising rights under this License with respect to
-the covered work, and you disclaim any intention to limit operation or
-modification of the work as a means of enforcing, against the work's
-users, your or third parties' legal rights to forbid circumvention of
-technological measures.
-
-  4. Conveying Verbatim Copies.
-
-  You may convey verbatim copies of the Program's source code as you
-receive it, in any medium, provided that you conspicuously and
-appropriately publish on each copy an appropriate copyright notice;
-keep intact all notices stating that this License and any
-non-permissive terms added in accord with section 7 apply to the code;
-keep intact all notices of the absence of any warranty; and give all
-recipients a copy of this License along with the Program.
-
-  You may charge any price or no price for each copy that you convey,
-and you may offer support or warranty protection for a fee.
-
-  5. Conveying Modified Source Versions.
-
-  You may convey a work based on the Program, or the modifications to
-produce it from the Program, in the form of source code under the
-terms of section 4, provided that you also meet all of these conditions:
-
-    a) The work must carry prominent notices stating that you modified
-    it, and giving a relevant date.
-
-    b) The work must carry prominent notices stating that it is
-    released under this License and any conditions added under section
-    7.  This requirement modifies the requirement in section 4 to
-    "keep intact all notices".
-
-    c) You must license the entire work, as a whole, under this
-    License to anyone who comes into possession of a copy.  This
-    License will therefore apply, along with any applicable section 7
-    additional terms, to the whole of the work, and all its parts,
-    regardless of how they are packaged.  This License gives no
-    permission to license the work in any other way, but it does not
-    invalidate such permission if you have separately received it.
-
-    d) If the work has interactive user interfaces, each must display
-    Appropriate Legal Notices; however, if the Program has interactive
-    interfaces that do not display Appropriate Legal Notices, your
-    work need not make them do so.
-
-  A compilation of a covered work with other separate and independent
-works, which are not by their nature extensions of the covered work,
-and which are not combined with it such as to form a larger program,
-in or on a volume of a storage or distribution medium, is called an
-"aggregate" if the compilation and its resulting copyright are not
-used to limit the access or legal rights of the compilation's users
-beyond what the individual works permit.  Inclusion of a covered work
-in an aggregate does not cause this License to apply to the other
-parts of the aggregate.
-
-  6. Conveying Non-Source Forms.
-
-  You may convey a covered work in object code form under the terms
-of sections 4 and 5, provided that you also convey the
-machine-readable Corresponding Source under the terms of this License,
-in one of these ways:
-
-    a) Convey the object code in, or embodied in, a physical product
-    (including a physical distribution medium), accompanied by the
-    Corresponding Source fixed on a durable physical medium
-    customarily used for software interchange.
-
-    b) Convey the object code in, or embodied in, a physical product
-    (including a physical distribution medium), accompanied by a
-    written offer, valid for at least three years and valid for as
-    long as you offer spare parts or customer support for that product
-    model, to give anyone who possesses the object code either (1) a
-    copy of the Corresponding Source for all the software in the
-    product that is covered by this License, on a durable physical
-    medium customarily used for software interchange, for a price no
-    more than your reasonable cost of physically performing this
-    conveying of source, or (2) access to copy the
-    Corresponding Source from a network server at no charge.
-
-    c) Convey individual copies of the object code with a copy of the
-    written offer to provide the Corresponding Source.  This
-    alternative is allowed only occasionally and noncommercially, and
-    only if you received the object code with such an offer, in accord
-    with subsection 6b.
-
-    d) Convey the object code by offering access from a designated
-    place (gratis or for a charge), and offer equivalent access to the
-    Corresponding Source in the same way through the same place at no
-    further charge.  You need not require recipients to copy the
-    Corresponding Source along with the object code.  If the place to
-    copy the object code is a network server, the Corresponding Source
-    may be on a different server (operated by you or a third party)
-    that supports equivalent copying facilities, provided you maintain
-    clear directions next to the object code saying where to find the
-    Corresponding Source.  Regardless of what server hosts the
-    Corresponding Source, you remain obligated to ensure that it is
-    available for as long as needed to satisfy these requirements.
-
-    e) Convey the object code using peer-to-peer transmission, provided
-    you inform other peers where the object code and Corresponding
-    Source of the work are being offered to the general public at no
-    charge under subsection 6d.
-
-  A separable portion of the object code, whose source code is excluded
-from the Corresponding Source as a System Library, need not be
-included in conveying the object code work.
-
-  A "User Product" is either (1) a "consumer product", which means any
-tangible personal property which is normally used for personal, family,
-or household purposes, or (2) anything designed or sold for incorporation
-into a dwelling.  In determining whether a product is a consumer product,
-doubtful cases shall be resolved in favor of coverage.  For a particular
-product received by a particular user, "normally used" refers to a
-typical or common use of that class of product, regardless of the status
-of the particular user or of the way in which the particular user
-actually uses, or expects or is expected to use, the product.  A product
-is a consumer product regardless of whether the product has substantial
-commercial, industrial or non-consumer uses, unless such uses represent
-the only significant mode of use of the product.
-
-  "Installation Information" for a User Product means any methods,
-procedures, authorization keys, or other information required to install
-and execute modified versions of a covered work in that User Product from
-a modified version of its Corresponding Source.  The information must
-suffice to ensure that the continued functioning of the modified object
-code is in no case prevented or interfered with solely because
-modification has been made.
-
-  If you convey an object code work under this section in, or with, or
-specifically for use in, a User Product, and the conveying occurs as
-part of a transaction in which the right of possession and use of the
-User Product is transferred to the recipient in perpetuity or for a
-fixed term (regardless of how the transaction is characterized), the
-Corresponding Source conveyed under this section must be accompanied
-by the Installation Information.  But this requirement does not apply
-if neither you nor any third party retains the ability to install
-modified object code on the User Product (for example, the work has
-been installed in ROM).
-
-  The requirement to provide Installation Information does not include a
-requirement to continue to provide support service, warranty, or updates
-for a work that has been modified or installed by the recipient, or for
-the User Product in which it has been modified or installed.  Access to a
-network may be denied when the modification itself materially and
-adversely affects the operation of the network or violates the rules and
-protocols for communication across the network.
-
-  Corresponding Source conveyed, and Installation Information provided,
-in accord with this section must be in a format that is publicly
-documented (and with an implementation available to the public in
-source code form), and must require no special password or key for
-unpacking, reading or copying.
-
-  7. Additional Terms.
-
-  "Additional permissions" are terms that supplement the terms of this
-License by making exceptions from one or more of its conditions.
-Additional permissions that are applicable to the entire Program shall
-be treated as though they were included in this License, to the extent
-that they are valid under applicable law.  If additional permissions
-apply only to part of the Program, that part may be used separately
-under those permissions, but the entire Program remains governed by
-this License without regard to the additional permissions.
-
-  When you convey a copy of a covered work, you may at your option
-remove any additional permissions from that copy, or from any part of
-it.  (Additional permissions may be written to require their own
-removal in certain cases when you modify the work.)  You may place
-additional permissions on material, added by you to a covered work,
-for which you have or can give appropriate copyright permission.
-
-  Notwithstanding any other provision of this License, for material you
-add to a covered work, you may (if authorized by the copyright holders of
-that material) supplement the terms of this License with terms:
-
-    a) Disclaiming warranty or limiting liability differently from the
-    terms of sections 15 and 16 of this License; or
-
-    b) Requiring preservation of specified reasonable legal notices or
-    author attributions in that material or in the Appropriate Legal
-    Notices displayed by works containing it; or
-
-    c) Prohibiting misrepresentation of the origin of that material, or
-    requiring that modified versions of such material be marked in
-    reasonable ways as different from the original version; or
-
-    d) Limiting the use for publicity purposes of names of licensors or
-    authors of the material; or
-
-    e) Declining to grant rights under trademark law for use of some
-    trade names, trademarks, or service marks; or
-
-    f) Requiring indemnification of licensors and authors of that
-    material by anyone who conveys the material (or modified versions of
-    it) with contractual assumptions of liability to the recipient, for
-    any liability that these contractual assumptions directly impose on
-    those licensors and authors.
-
-  All other non-permissive additional terms are considered "further
-restrictions" within the meaning of section 10.  If the Program as you
-received it, or any part of it, contains a notice stating that it is
-governed by this License along with a term that is a further
-restriction, you may remove that term.  If a license document contains
-a further restriction but permits relicensing or conveying under this
-License, you may add to a covered work material governed by the terms
-of that license document, provided that the further restriction does
-not survive such relicensing or conveying.
-
-  If you add terms to a covered work in accord with this section, you
-must place, in the relevant source files, a statement of the
-additional terms that apply to those files, or a notice indicating
-where to find the applicable terms.
-
-  Additional terms, permissive or non-permissive, may be stated in the
-form of a separately written license, or stated as exceptions;
-the above requirements apply either way.
-
-  8. Termination.
-
-  You may not propagate or modify a covered work except as expressly
-provided under this License.  Any attempt otherwise to propagate or
-modify it is void, and will automatically terminate your rights under
-this License (including any patent licenses granted under the third
-paragraph of section 11).
-
-  However, if you cease all violation of this License, then your
-license from a particular copyright holder is reinstated (a)
-provisionally, unless and until the copyright holder explicitly and
-finally terminates your license, and (b) permanently, if the copyright
-holder fails to notify you of the violation by some reasonable means
-prior to 60 days after the cessation.
-
-  Moreover, your license from a particular copyright holder is
-reinstated permanently if the copyright holder notifies you of the
-violation by some reasonable means, this is the first time you have
-received notice of violation of this License (for any work) from that
-copyright holder, and you cure the violation prior to 30 days after
-your receipt of the notice.
-
-  Termination of your rights under this section does not terminate the
-licenses of parties who have received copies or rights from you under
-this License.  If your rights have been terminated and not permanently
-reinstated, you do not qualify to receive new licenses for the same
-material under section 10.
-
-  9. Acceptance Not Required for Having Copies.
-
-  You are not required to accept this License in order to receive or
-run a copy of the Program.  Ancillary propagation of a covered work
-occurring solely as a consequence of using peer-to-peer transmission
-to receive a copy likewise does not require acceptance.  However,
-nothing other than this License grants you permission to propagate or
-modify any covered work.  These actions infringe copyright if you do
-not accept this License.  Therefore, by modifying or propagating a
-covered work, you indicate your acceptance of this License to do so.
-
-  10. Automatic Licensing of Downstream Recipients.
-
-  Each time you convey a covered work, the recipient automatically
-receives a license from the original licensors, to run, modify and
-propagate that work, subject to this License.  You are not responsible
-for enforcing compliance by third parties with this License.
-
-  An "entity transaction" is a transaction transferring control of an
-organization, or substantially all assets of one, or subdividing an
-organization, or merging organizations.  If propagation of a covered
-work results from an entity transaction, each party to that
-transaction who receives a copy of the work also receives whatever
-licenses to the work the party's predecessor in interest had or could
-give under the previous paragraph, plus a right to possession of the
-Corresponding Source of the work from the predecessor in interest, if
-the predecessor has it or can get it with reasonable efforts.
-
-  You may not impose any further restrictions on the exercise of the
-rights granted or affirmed under this License.  For example, you may
-not impose a license fee, royalty, or other charge for exercise of
-rights granted under this License, and you may not initiate litigation
-(including a cross-claim or counterclaim in a lawsuit) alleging that
-any patent claim is infringed by making, using, selling, offering for
-sale, or importing the Program or any portion of it.
-
-  11. Patents.
-
-  A "contributor" is a copyright holder who authorizes use under this
-License of the Program or a work on which the Program is based.  The
-work thus licensed is called the contributor's "contributor version".
-
-  A contributor's "essential patent claims" are all patent claims
-owned or controlled by the contributor, whether already acquired or
-hereafter acquired, that would be infringed by some manner, permitted
-by this License, of making, using, or selling its contributor version,
-but do not include claims that would be infringed only as a
-consequence of further modification of the contributor version.  For
-purposes of this definition, "control" includes the right to grant
-patent sublicenses in a manner consistent with the requirements of
-this License.
-
-  Each contributor grants you a non-exclusive, worldwide, royalty-free
-patent license under the contributor's essential patent claims, to
-make, use, sell, offer for sale, import and otherwise run, modify and
-propagate the contents of its contributor version.
-
-  In the following three paragraphs, a "patent license" is any express
-agreement or commitment, however denominated, not to enforce a patent
-(such as an express permission to practice a patent or covenant not to
-sue for patent infringement).  To "grant" such a patent license to a
-party means to make such an agreement or commitment not to enforce a
-patent against the party.
-
-  If you convey a covered work, knowingly relying on a patent license,
-and the Corresponding Source of the work is not available for anyone
-to copy, free of charge and under the terms of this License, through a
-publicly available network server or other readily accessible means,
-then you must either (1) cause the Corresponding Source to be so
-available, or (2) arrange to deprive yourself of the benefit of the
-patent license for this particular work, or (3) arrange, in a manner
-consistent with the requirements of this License, to extend the patent
-license to downstream recipients.  "Knowingly relying" means you have
-actual knowledge that, but for the patent license, your conveying the
-covered work in a country, or your recipient's use of the covered work
-in a country, would infringe one or more identifiable patents in that
-country that you have reason to believe are valid.
-
-  If, pursuant to or in connection with a single transaction or
-arrangement, you convey, or propagate by procuring conveyance of, a
-covered work, and grant a patent license to some of the parties
-receiving the covered work authorizing them to use, propagate, modify
-or convey a specific copy of the covered work, then the patent license
-you grant is automatically extended to all recipients of the covered
-work and works based on it.
-
-  A patent license is "discriminatory" if it does not include within
-the scope of its coverage, prohibits the exercise of, or is
-conditioned on the non-exercise of one or more of the rights that are
-specifically granted under this License.  You may not convey a covered
-work if you are a party to an arrangement with a third party that is
-in the business of distributing software, under which you make payment
-to the third party based on the extent of your activity of conveying
-the work, and under which the third party grants, to any of the
-parties who would receive the covered work from you, a discriminatory
-patent license (a) in connection with copies of the covered work
-conveyed by you (or copies made from those copies), or (b) primarily
-for and in connection with specific products or compilations that
-contain the covered work, unless you entered into that arrangement,
-or that patent license was granted, prior to 28 March 2007.
-
-  Nothing in this License shall be construed as excluding or limiting
-any implied license or other defenses to infringement that may
-otherwise be available to you under applicable patent law.
-
-  12. No Surrender of Others' Freedom.
-
-  If conditions are imposed on you (whether by court order, agreement or
-otherwise) that contradict the conditions of this License, they do not
-excuse you from the conditions of this License.  If you cannot convey a
-covered work so as to satisfy simultaneously your obligations under this
-License and any other pertinent obligations, then as a consequence you may
-not convey it at all.  For example, if you agree to terms that obligate you
-to collect a royalty for further conveying from those to whom you convey
-the Program, the only way you could satisfy both those terms and this
-License would be to refrain entirely from conveying the Program.
-
-  13. Remote Network Interaction; Use with the GNU General Public License.
-
-  Notwithstanding any other provision of this License, if you modify the
-Program, your modified version must prominently offer all users
-interacting with it remotely through a computer network (if your version
-supports such interaction) an opportunity to receive the Corresponding
-Source of your version by providing access to the Corresponding Source
-from a network server at no charge, through some standard or customary
-means of facilitating copying of software.  This Corresponding Source
-shall include the Corresponding Source for any work covered by version 3
-of the GNU General Public License that is incorporated pursuant to the
-following paragraph.
-
-  Notwithstanding any other provision of this License, you have
-permission to link or combine any covered work with a work licensed
-under version 3 of the GNU General Public License into a single
-combined work, and to convey the resulting work.  The terms of this
-License will continue to apply to the part which is the covered work,
-but the work with which it is combined will remain governed by version
-3 of the GNU General Public License.
-
-  14. Revised Versions of this License.
-
-  The Free Software Foundation may publish revised and/or new versions of
-the GNU Affero General Public License from time to time.  Such new versions
-will be similar in spirit to the present version, but may differ in detail to
-address new problems or concerns.
-
-  Each version is given a distinguishing version number.  If the
-Program specifies that a certain numbered version of the GNU Affero General
-Public License "or any later version" applies to it, you have the
-option of following the terms and conditions either of that numbered
-version or of any later version published by the Free Software
-Foundation.  If the Program does not specify a version number of the
-GNU Affero General Public License, you may choose any version ever published
-by the Free Software Foundation.
-
-  If the Program specifies that a proxy can decide which future
-versions of the GNU Affero General Public License can be used, that proxy's
-public statement of acceptance of a version permanently authorizes you
-to choose that version for the Program.
-
-  Later license versions may give you additional or different
-permissions.  However, no additional obligations are imposed on any
-author or copyright holder as a result of your choosing to follow a
-later version.
-
-  15. Disclaimer of Warranty.
-
-  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
-APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
-HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
-OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
-THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
-IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
-ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
-
-  16. Limitation of Liability.
-
-  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
-THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
-GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
-USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
-DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
-PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
-EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
-SUCH DAMAGES.
-
-  17. Interpretation of Sections 15 and 16.
-
-  If the disclaimer of warranty and limitation of liability provided
-above cannot be given local legal effect according to their terms,
-reviewing courts shall apply local law that most closely approximates
-an absolute waiver of all civil liability in connection with the
-Program, unless a warranty or assumption of liability accompanies a
-copy of the Program in return for a fee.
-
-                     END OF TERMS AND CONDITIONS
-
-            How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
-state the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as published
-    by the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Affero General Public License for more details.
-
-    You should have received a copy of the GNU Affero General Public License
-    along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-Also add information on how to contact you by electronic and paper mail.
-
-  If your software can interact with users remotely through a computer
-network, you should also make sure that it provides a way for users to
-get its source.  For example, if your program is a web application, its
-interface could display a "Source" link that leads users to an archive
-of the code.  There are many ways you could offer source, and different
-solutions will be better for different programs; see section 13 for the
-specific requirements.
-
-  You should also get your employer (if you work as a programmer) or school,
-if any, to sign a "copyright disclaimer" for the program, if necessary.
-For more information on this, and how to apply and follow the GNU AGPL, see
-<https://www.gnu.org/licenses/>.

MIRRORS

@@ -0,0 +1,4 @@
+git@github.com:kevinveenbirkenbach/swap-forge.git
+ssh://git@git.veen.world:2201/kevinveenbirkenbach/swap-forge.git
+ssh://git@code.infinito.nexus:2201/kevinveenbirkenbach/swap-forge.git
+https://pypi.org/project/swap-forge/

Makefile

@@ -0,0 +1,50 @@
+SHELL := /usr/bin/env bash
+
+.PHONY: help lint lint-docs format test test-unit test-integration test-e2e clean
+
+PY ?= python3
+E2E_IMAGE ?= swap-forge-e2e
+MD_LINT_IMAGE ?= davidanson/markdownlint-cli2:latest
+MERMAID_IMAGE ?= minlag/mermaid-cli:latest
+
+export PYTHONPATH := $(CURDIR)/src
+
+help:
+	@echo "Targets:"
+	@echo "  make lint             - ruff check + ruff format --check"
+	@echo "  make lint-docs        - markdownlint + mermaid diagram validation"
+	@echo "  make format           - apply ruff format"
+	@echo "  make test             - unit + integration tests"
+	@echo "  make test-unit        - unit tests only"
+	@echo "  make test-integration - integration tests only"
+	@echo "  make test-e2e         - install and exercise the CLI in a container"
+	@echo "  make clean            - remove caches"
+
+lint:
+	ruff check .
+	ruff format --check .
+
+# The repository is mounted read-only: mermaid-cli writes its SVGs next to the
+# output file, which must never land in the working tree.
+lint-docs:
+	docker run --rm -v "$(CURDIR)":/workdir $(MD_LINT_IMAGE) "**/*.md"
+	docker run --rm -v "$(CURDIR)":/data:ro -w /tmp $(MERMAID_IMAGE) -i /data/README.md -o /tmp/out.md
+
+format:
+	ruff format .
+
+test: test-unit test-integration
+
+test-unit:
+	$(PY) -m unittest discover -s tests/unit -t . -p "test_*.py"
+
+test-integration:
+	$(PY) -m unittest discover -s tests/integration -t . -p "test_*.py"
+
+test-e2e:
+	docker build -f tests/e2e/Dockerfile -t $(E2E_IMAGE) .
+	docker run --rm $(E2E_IMAGE)
+
+clean:
+	rm -rf .pytest_cache .ruff_cache .mypy_cache
+	find . -type d -name "__pycache__" -print0 | xargs -0 -r rm -rf

README.md

@@ -1,2 +1,139 @@
-# create-linux-swapfile
-Creates a linux swapfile
+# SwapForge (swap-forge) 🔄
+
+[![GitHub Sponsors](https://img.shields.io/badge/Sponsor-GitHub%20Sponsors-blue?logo=github)](https://github.com/sponsors/kevinveenbirkenbach) [![Patreon](https://img.shields.io/badge/Support-Patreon-orange?logo=patreon)](https://www.patreon.com/c/kevinveenbirkenbach) [![Buy Me a Coffee](https://img.shields.io/badge/Buy%20me%20a%20Coffee-Funding-yellow?logo=buymeacoffee)](https://buymeacoffee.com/kevinveenbirkenbach) [![PayPal](https://img.shields.io/badge/Donate-PayPal-blue?logo=paypal)](https://s.veen.world/paypaldonate)
+
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE) [![GitHub stars](https://img.shields.io/github/stars/kevinveenbirkenbach/swap-forge.svg?style=social)](https://github.com/kevinveenbirkenbach/swap-forge/stargazers)
+
+SwapForge is a small Python CLI for creating and managing Linux swapfiles. Whether you need to boost system performance or add swap space to your setup, SwapForge automates the process quickly and reliably — and it knows the difference between btrfs and everything else.
+
+---
+
+## 🧭 How it works
+
+```mermaid
+flowchart TD
+    A["swap-forge SIZE"] --> B["parse SIZE into MiB"]
+    B --> B2{"parsable?"}
+    B2 -- no --> X["Invalid size format - exit 1"]
+    B2 -- yes --> C["findmnt -no FSTYPE /"]
+    C --> D{"root filesystem is btrfs?"}
+    D -- yes --> E["target: /var/swap/swapfile"]
+    D -- no --> F["target: /swapfile"]
+    E --> G["read the size of the existing swapfile"]
+    F --> G
+    G --> H{"same size already?"}
+    H -- yes --> Y["Skipping - exit 0"]
+    H -- no --> I{"a swapfile is already there?"}
+    I -- yes --> J["swapoff, delete it, drop its fstab line"]
+    I -- no --> K
+    J --> K{"root filesystem is btrfs?"}
+    K -- yes --> L["chattr +C, turn compression off, allocate with dd"]
+    K -- no --> M["allocate with fallocate"]
+    L --> N["chmod 600"]
+    M --> N
+    N --> O["mkswap"]
+    O --> P["swapon"]
+    P --> Q["append the entry to /etc/fstab"]
+```
+
+The fstab entry is written **after** activation succeeds, so a failed run never leaves a half-written fstab behind.
+
+---
+
+## 🛠 Features
+
+- **Automated Swapfile Creation:** Easily create a swapfile with a specified size.
+- **Btrfs Aware:** Disables copy-on-write and compression on the swap directory and allocates with `dd`; other filesystems use `fallocate`.
+- **FSTAB Integration:** Automatically updates `/etc/fstab` to ensure the swapfile is mounted at boot.
+- **Safety Checks:** Skips creation when a swapfile of the correct size already exists, and recreates it when the size differs.
+- **Simple CLI Interface:** Run the command with a single argument.
+
+---
+
+## 📥 Installation
+
+```bash
+pip install swap-forge
+```
+
+pip is the single supported installation path.
+
+The package installs **two** identical commands: `swap-forge` (primary) and `swafo` (kept for older documentation and scripts).
+
+---
+
+## 🔧 Requirements
+
+- **Python 3.10+** 🐍
+- **root privileges** — the tool writes `/etc/fstab` and activates swap
+- Always required on `PATH`: `findmnt`, `swapoff`, `chmod`, `mkswap`, `swapon`
+- On a **btrfs** root additionally: `chattr`, `btrfs`, `dd`
+- On any **other** root filesystem additionally: `fallocate`
+
+If a required command is missing, the tool exits with code `127` and a one‑line error instead of a traceback.
+
+---
+
+## 🚀 Usage
+
+Run SwapForge by specifying the desired swapfile size. For example, to create a 2G swapfile:
+
+```bash
+sudo swap-forge 2G
+```
+
+Accepted sizes are whole numbers with an optional unit: `2048`, `2048M`, `2048MB`, `64G`, `64GB`. Without a unit the value is read as MiB.
+
+The swapfile location follows the root filesystem:
+
+| Root filesystem | Swapfile |
+| --- | --- |
+| `btrfs` | `/var/swap/swapfile` |
+| anything else | `/swapfile` |
+
+SwapForge compares the existing swapfile against the requested size, skips when they match, and otherwise removes the old one — including its `/etc/fstab` line — before creating the new one.
+
+### Exit codes
+
+| Code | Meaning |
+| --- | --- |
+| `0` | Swapfile is in place, either created or already correct. |
+| `1` | Invalid size argument, or one of the swap commands failed. |
+| `2` | Invalid command line arguments. |
+| `127` | A required command is not installed. |
+
+---
+
+## 🧪 Development
+
+```bash
+make lint              # ruff check + ruff format --check
+make format            # apply ruff format
+make test              # unit + integration tests
+make test-unit
+make test-integration
+make test-e2e          # install the package in a container and exercise the CLI
+```
+
+Tests run against the working tree — the `Makefile` puts `src/` on `PYTHONPATH`, so no install is needed. Every command execution is mocked and `fstab` handling is exercised against a temporary file, so the suite never touches real swap.
+
+---
+
+## 🧑‍💻 Author
+
+Developed by **Kevin Veen-Birkenbach**
+
+- 📧 [kevin@veen.world](mailto:kevin@veen.world)
+- 🌐 [https://www.veen.world](https://www.veen.world)
+
+---
+
+## 📜 License
+
+This project is licensed under the **MIT License**.
+
+---
+
+## 🤝 Contributions
+
+Contributions are welcome! Feel free to fork the repository, submit pull requests, or open issues if you have suggestions or encounter any problems. Let's make Linux swap management easier together! 😊

create-linux-swapfile.sh

@@ -1,14 +0,0 @@
-#!/bin/bash
-FSTAB_SWAP_ENTRY="/swapfile none swap defaults 0 0"
-SWAP_FILE="/swapfile"
-FSTAB_FILE="/etc/fstab"
-if grep -q "$FSTAB_SWAP_ENTRY" "$FSTAB_FILE"; then
-	echo "Skipping creation of swap partion because entry allready exists in \"$FSTAB_FILE\"!"
-else
-	echo "Creating swap partition..." &&
-	sudo fallocate -l "$1" "$SWAP_FILE" &&
-	sudo chmod 600 "$SWAP_FILE" &&
-	sudo mkswap "$SWAP_FILE" &&
-	sudo swapon "$SWAP_FILE" &&
-	sudo sh -c "echo \"$FSTAB_SWAP_ENTRY\">>\"$FSTAB_FILE\"" || exit 1
-fi

pyproject.toml

@@ -0,0 +1,36 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "swap-forge"
+version = "1.0.0"
+description = "Create, resize and register a Linux swapfile, btrfs aware."
+readme = "README.md"
+requires-python = ">=3.10"
+license = { text = "MIT" }
+authors = [{ name = "Kevin Veen-Birkenbach", email = "kevin@veen.world" }]
+keywords = ["swap", "swapfile", "btrfs", "linux", "cli"]
+dependencies = []
+
+[project.urls]
+Homepage = "https://www.veen.world/"
+Repository = "https://github.com/kevinveenbirkenbach/swap-forge"
+
+[project.scripts]
+swap-forge = "swap_forge.cli:main"
+swafo = "swap_forge.cli:main"
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/swap_forge"]
+core-metadata-version = "2.4"
+
+[tool.hatch.build.targets.sdist]
+core-metadata-version = "2.4"
+
+[tool.ruff]
+line-length = 88
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "B", "UP"]
+ignore = ["E501"]

src/swap_forge/__main__.py

@@ -0,0 +1,6 @@
+import sys
+
+from swap_forge.cli import main
+
+if __name__ == "__main__":
+    sys.exit(main())

src/swap_forge/cli.py

@@ -0,0 +1,74 @@
+import argparse
+import sys
+from subprocess import CalledProcessError
+
+from swap_forge.core import (
+    EXIT_COMMAND_FAILED,
+    EXIT_MISSING_BINARY,
+    MissingBinaryError,
+    create_swap,
+    detect_root_fs,
+    get_swap_size,
+    parse_size_to_mib,
+    remove_swap,
+    swap_path_for,
+)
+
+
+def build_parser():
+    """Return the argument parser for the swap-forge command."""
+    parser = argparse.ArgumentParser(description="SwapForge Python edition")
+    parser.add_argument("size", help="Swapfile size (e.g. 2048M or 64G)")
+    return parser
+
+
+def main(argv=None):
+    """Create or resize the system swapfile.
+
+    Args:
+        argv: Argument list, defaults to sys.argv[1:].
+
+    Returns:
+        Process exit code.
+    """
+    args = build_parser().parse_args(argv)
+
+    try:
+        new_size = parse_size_to_mib(args.size)
+    except ValueError as error:
+        print(f"Error: {error}", file=sys.stderr)
+        return 1
+
+    try:
+        fs = detect_root_fs()
+        path = swap_path_for(fs)
+        old_size = get_swap_size(path)
+
+        if old_size == new_size and old_size > 0:
+            print(
+                f"Swapfile {path} already exists with correct size "
+                f"({old_size} MiB). Skipping."
+            )
+            return 0
+
+        if old_size > 0:
+            print(
+                f"Existing swapfile {path} has size {old_size} MiB, "
+                f"expected {new_size} MiB. Recreating..."
+            )
+            remove_swap(path)
+
+        create_swap(path, new_size, fs)
+    except MissingBinaryError as error:
+        print(f"Error: {error}", file=sys.stderr)
+        return EXIT_MISSING_BINARY
+    except CalledProcessError as error:
+        command = error.cmd[0] if isinstance(error.cmd, list | tuple) else error.cmd
+        print(
+            f"Error: '{command}' failed with exit code {error.returncode}",
+            file=sys.stderr,
+        )
+        return EXIT_COMMAND_FAILED
+
+    print("Done.")
+    return 0

src/swap_forge/core.py

@@ -0,0 +1,160 @@
+import re
+import subprocess
+from pathlib import Path
+
+FSTAB_FILE = Path("/etc/fstab")
+BTRFS_SWAP_DIR = Path("/var/swap")
+BTRFS_SWAP_PATH = BTRFS_SWAP_DIR / "swapfile"
+DEFAULT_SWAP_PATH = Path("/swapfile")
+
+SIZE_PATTERN = re.compile(r"^(\d+)([gGmM]?[bB]?)?$")
+MIB_PER_GIB = 1024
+
+REQUIRED_BINARIES = ("findmnt", "swapoff", "chmod", "mkswap", "swapon")
+BTRFS_BINARIES = ("chattr", "btrfs", "dd")
+NON_BTRFS_BINARIES = ("fallocate",)
+EXIT_MISSING_BINARY = 127
+EXIT_COMMAND_FAILED = 1
+
+
+class MissingBinaryError(RuntimeError):
+    """A required external command is not installed.
+
+    Args:
+        binary: Name of the missing executable.
+    """
+
+    def __init__(self, binary):
+        super().__init__(f"required command '{binary}' is not installed")
+        self.binary = binary
+
+
+def run(cmd, check=True, capture=False):
+    """Run a command and return the completed process.
+
+    Args:
+        cmd: Command argument list.
+        check: Raise CalledProcessError when the command fails.
+        capture: Capture stdout and stderr as text.
+    """
+    try:
+        if capture:
+            return subprocess.run(cmd, check=check, capture_output=True, text=True)
+        return subprocess.run(cmd, check=check)
+    except FileNotFoundError as error:
+        raise MissingBinaryError(cmd[0]) from error
+
+
+def detect_root_fs():
+    """Return the filesystem type mounted at /."""
+    return run(["findmnt", "-no", "FSTYPE", "/"], capture=True).stdout.strip()
+
+
+def parse_size_to_mib(size):
+    """Convert a size such as '64G' or '2048M' into MiB.
+
+    Args:
+        size: Size string with an optional G/M unit, defaulting to MiB.
+    """
+    match = SIZE_PATTERN.match(size.strip())
+    if not match:
+        raise ValueError(f"Invalid size format: {size}")
+
+    number, unit = match.groups()
+    unit = (unit or "M").lower()
+
+    if unit in ("g", "gb"):
+        return int(number) * MIB_PER_GIB
+    if unit in ("m", "mb"):
+        return int(number)
+    raise ValueError(f"Unsupported unit: {unit}")
+
+
+def get_swap_size(path):
+    """Return the size of the swapfile in MiB, or 0 when it does not exist.
+
+    Args:
+        path: Path of the swapfile.
+    """
+    if not path.exists():
+        return 0
+    return path.stat().st_size // (1024 * 1024)
+
+
+def swap_fstab_line(path):
+    """Return the fstab line registering the given swapfile."""
+    return f"{path} none swap sw 0 0"
+
+
+def remove_swap(path, fstab=FSTAB_FILE):
+    """Disable the swapfile and drop it plus its fstab entry.
+
+    Args:
+        path: Path of the swapfile.
+        fstab: Path of the fstab file to clean up.
+    """
+    run(["swapoff", str(path)], check=False)
+    if path.exists():
+        path.unlink()
+
+    if not fstab.exists():
+        return
+
+    kept = [
+        line
+        for line in fstab.read_text().splitlines()
+        if not re.search(rf"^{re.escape(str(path))}\s+none\s+swap", line)
+    ]
+    fstab.write_text("\n".join(kept) + "\n")
+
+
+def create_swap(path, size_mib, fs, fstab=FSTAB_FILE):
+    """Create, activate and register a swapfile.
+
+    Args:
+        path: Path of the swapfile.
+        size_mib: Desired size in MiB.
+        fs: Filesystem type of the root mount.
+        fstab: Path of the fstab file to append to.
+    """
+    if fs == "btrfs":
+        print(f"Creating {size_mib} MiB swapfile on btrfs at {path}")
+        path.parent.mkdir(parents=True, exist_ok=True)
+        run(["chattr", "+C", str(path.parent)], check=False)
+        run(
+            [
+                "btrfs",
+                "property",
+                "set",
+                "-ts",
+                str(path.parent),
+                "compression",
+                "none",
+            ],
+            check=False,
+        )
+        run(
+            [
+                "dd",
+                "if=/dev/zero",
+                f"of={path}",
+                "bs=1M",
+                f"count={size_mib}",
+                "status=progress",
+            ]
+        )
+    else:
+        print(f"Creating {size_mib} MiB swapfile on {fs} at {path}")
+        run(["fallocate", "-l", f"{size_mib}M", str(path)])
+
+    run(["chmod", "600", str(path)])
+    run(["mkswap", str(path)])
+    run(["swapon", str(path)])
+
+    with fstab.open("a") as handle:
+        handle.write(swap_fstab_line(path) + "\n")
+
+
+def swap_path_for(fs):
+    """Return the swapfile path matching the given root filesystem type."""
+    return BTRFS_SWAP_PATH if fs == "btrfs" else DEFAULT_SWAP_PATH

tests/e2e/Dockerfile

@@ -0,0 +1,12 @@
+FROM python:3.12-slim
+
+RUN apt-get update \
+ && apt-get install -y --no-install-recommends util-linux e2fsprogs btrfs-progs \
+ && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /src
+COPY . /src
+
+RUN pip install --no-cache-dir .
+
+CMD ["sh", "/src/tests/e2e/run.sh"]

tests/e2e/run.sh

@@ -0,0 +1,103 @@
+#!/bin/sh
+# An unprivileged container cannot activate swap, so the run is expected to fail
+# at mkswap or swapon - which of the two depends on the host's /proc/swaps.
+# Everything before it - findmnt, fallocate, chmod - runs for real.
+set -eu
+
+fail() {
+    echo "FAIL: $1" >&2
+    exit 1
+}
+
+SWAPFORGE="$(command -v swap-forge)" || fail "swap-forge is not on PATH after install"
+echo "ok: swap-forge installed at ${SWAPFORGE}"
+
+command -v swafo >/dev/null || fail "the swafo alias is not on PATH after install"
+echo "ok: swafo alias installed"
+
+case "${SWAPFORGE}" in
+    /usr/local/bin/*) ;;
+    *) fail "swap-forge resolved to ${SWAPFORGE}, outside the install prefix" ;;
+esac
+echo "ok: resolved from the installed package, not the source tree"
+
+for binary in findmnt swapoff chmod mkswap swapon fallocate chattr btrfs dd; do
+    command -v "${binary}" >/dev/null || fail "${binary} is missing from the image"
+done
+echo "ok: every declared binary is present"
+
+swap-forge --help | grep -q "Swapfile size" || fail "--help does not describe the tool"
+echo "ok: --help"
+
+set +e
+swap-forge >/dev/null 2>&1
+status=$?
+set -e
+[ "${status}" -eq 2 ] || fail "a missing size exited ${status}, expected 2"
+echo "ok: a missing size exits 2"
+
+set +e
+output="$(swap-forge 64T 2>&1)"
+status=$?
+set -e
+[ "${status}" -eq 1 ] || fail "an invalid size exited ${status}, expected 1"
+echo "${output}" | grep -q "Invalid size format" || fail "invalid size message wrong"
+if echo "${output}" | grep -q "Traceback"; then
+    fail "an invalid size produced a traceback"
+fi
+echo "ok: an invalid size exits 1 without a traceback"
+
+printf 'UUID=deadbeef / ext4 defaults 0 1\n' >/etc/fstab
+cp /etc/fstab /tmp/fstab.before
+
+set +e
+output="$(swap-forge 8M 2>&1)"
+status=$?
+set -e
+[ "${status}" -eq 1 ] || fail "the blocked activation exited ${status}, expected 1"
+echo "${output}" | grep -q "Creating 8 MiB swapfile" || fail "the creation banner is missing"
+echo "${output}" | grep -qE "'(mkswap|swapon)' failed with exit code" || fail "the blocked activation was not reported cleanly"
+if echo "${output}" | grep -q "Traceback"; then
+    fail "the blocked activation produced a traceback"
+fi
+echo "ok: real fallocate and chmod ran; the blocked activation exits 1 cleanly"
+
+[ -f /swapfile ] || fail "/swapfile was not created"
+size="$(stat -c %s /swapfile)"
+[ "${size}" -eq 8388608 ] || fail "/swapfile is ${size} bytes, expected 8388608"
+echo "ok: /swapfile exists with exactly the requested size"
+
+cmp -s /etc/fstab /tmp/fstab.before || fail "/etc/fstab changed although activation failed"
+echo "ok: /etc/fstab is untouched when activation fails"
+
+set +e
+output="$(swap-forge 8M 2>&1)"
+status=$?
+set -e
+[ "${status}" -eq 0 ] || fail "the idempotent rerun exited ${status}, expected 0"
+echo "${output}" | grep -q "already exists with correct size (8 MiB). Skipping." \
+    || fail "an existing swapfile of the right size was not detected"
+echo "ok: a rerun with the same size is a no-op - the idempotency the role relies on"
+
+set +e
+output="$(swap-forge 12M 2>&1)"
+status=$?
+set -e
+echo "${output}" | grep -q "has size 8 MiB, expected 12 MiB. Recreating..." \
+    || fail "a size change did not trigger a recreation"
+size="$(stat -c %s /swapfile)"
+[ "${size}" -eq 12582912 ] || fail "/swapfile is ${size} bytes after resize, expected 12582912"
+echo "ok: a different size really removes and recreates the swapfile"
+
+cmp -s /etc/fstab /tmp/fstab.before || fail "/etc/fstab changed during the resize cycle"
+echo "ok: /etc/fstab survived the resize cycle byte for byte"
+
+set +e
+output="$(env PATH=/nonexistent-bin "${SWAPFORGE}" 8M 2>&1)"
+status=$?
+set -e
+[ "${status}" -eq 127 ] || fail "missing findmnt exited ${status}, expected 127"
+echo "${output}" | grep -q "required command 'findmnt' is not installed" || fail "missing findmnt message wrong"
+echo "ok: missing findmnt exits 127 with a clean message"
+
+echo "ALL E2E CHECKS PASSED"

tests/integration/test_cli.py

@@ -0,0 +1,62 @@
+import os
+import subprocess
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+SRC_DIR = REPO_ROOT / "src"
+
+
+def run_cli(*args, path=None):
+    """Run 'python -m swap_forge' with the working tree on PYTHONPATH.
+
+    Args:
+        args: Command line arguments for the CLI.
+        path: Replacement PATH, used to hide the findmnt binary.
+    """
+    env = dict(os.environ)
+    env["PYTHONPATH"] = str(SRC_DIR)
+    if path is not None:
+        env["PATH"] = str(path)
+    return subprocess.run(
+        [sys.executable, "-m", "swap_forge", *args],
+        capture_output=True,
+        text=True,
+        env=env,
+        check=False,
+    )
+
+
+class TestCli(unittest.TestCase):
+    def test_help_exits_zero(self):
+        result = run_cli("--help")
+
+        self.assertEqual(result.returncode, 0, result.stderr)
+        self.assertIn("Swapfile size", result.stdout)
+
+    def test_missing_size_is_rejected(self):
+        result = run_cli()
+
+        self.assertEqual(result.returncode, 2)
+        self.assertIn("size", result.stderr)
+
+    def test_missing_findmnt_fails_cleanly(self):
+        with tempfile.TemporaryDirectory() as empty:
+            result = run_cli("2048M", path=empty)
+
+        self.assertEqual(result.returncode, 127)
+        self.assertIn("required command 'findmnt' is not installed", result.stderr)
+        self.assertNotIn("Traceback", result.stderr)
+
+    def test_invalid_size_fails_without_a_traceback(self):
+        result = run_cli("64T")
+
+        self.assertEqual(result.returncode, 1)
+        self.assertIn("Invalid size format", result.stderr)
+        self.assertNotIn("Traceback", result.stderr)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/unit/test_cli.py

@@ -0,0 +1,63 @@
+import unittest
+from pathlib import Path
+from subprocess import CalledProcessError
+from unittest import mock
+
+from swap_forge.cli import main
+
+
+class TestMain(unittest.TestCase):
+    def _run(self, argv, fs="ext4", old_size=0):
+        with (
+            mock.patch("swap_forge.cli.detect_root_fs", return_value=fs),
+            mock.patch("swap_forge.cli.swap_path_for", return_value=Path("/swapfile")),
+            mock.patch("swap_forge.cli.get_swap_size", return_value=old_size),
+            mock.patch("swap_forge.cli.remove_swap") as remove,
+            mock.patch("swap_forge.cli.create_swap") as create,
+        ):
+            exit_code = main(argv)
+        return exit_code, remove, create
+
+    def test_creates_a_missing_swapfile(self):
+        exit_code, remove, create = self._run(["2048M"])
+
+        remove.assert_not_called()
+        create.assert_called_once_with(Path("/swapfile"), 2048, "ext4")
+        self.assertEqual(exit_code, 0)
+
+    def test_matching_size_is_left_alone(self):
+        exit_code, remove, create = self._run(["2048M"], old_size=2048)
+
+        remove.assert_not_called()
+        create.assert_not_called()
+        self.assertEqual(exit_code, 0)
+
+    def test_wrong_size_is_recreated(self):
+        exit_code, remove, create = self._run(["4G"], old_size=2048)
+
+        remove.assert_called_once_with(Path("/swapfile"))
+        create.assert_called_once_with(Path("/swapfile"), 4096, "ext4")
+        self.assertEqual(exit_code, 0)
+
+    def test_failing_command_reports_cleanly(self):
+        with (
+            mock.patch("swap_forge.cli.detect_root_fs", return_value="ext4"),
+            mock.patch("swap_forge.cli.swap_path_for", return_value=Path("/swapfile")),
+            mock.patch("swap_forge.cli.get_swap_size", return_value=0),
+            mock.patch("swap_forge.cli.create_swap") as create,
+        ):
+            create.side_effect = CalledProcessError(255, ["swapon", "/swapfile"])
+            exit_code = main(["2048M"])
+
+        self.assertEqual(exit_code, 1)
+
+    def test_invalid_size_exits_non_zero(self):
+        with mock.patch("swap_forge.cli.detect_root_fs") as detect:
+            exit_code = main(["64T"])
+
+        detect.assert_not_called()
+        self.assertEqual(exit_code, 1)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/unit/test_core.py

@@ -0,0 +1,173 @@
+import tempfile
+import unittest
+from pathlib import Path
+from unittest import mock
+
+from swap_forge.core import (
+    BTRFS_BINARIES,
+    BTRFS_SWAP_PATH,
+    DEFAULT_SWAP_PATH,
+    NON_BTRFS_BINARIES,
+    REQUIRED_BINARIES,
+    MissingBinaryError,
+    create_swap,
+    get_swap_size,
+    parse_size_to_mib,
+    remove_swap,
+    run,
+    swap_fstab_line,
+    swap_path_for,
+)
+
+
+class TestRequiredBinaries(unittest.TestCase):
+    def test_declares_every_external_command_the_package_calls(self):
+        declared = (
+            set(REQUIRED_BINARIES) | set(BTRFS_BINARIES) | set(NON_BTRFS_BINARIES)
+        )
+
+        self.assertEqual(
+            declared,
+            {
+                "findmnt",
+                "swapoff",
+                "chmod",
+                "mkswap",
+                "swapon",
+                "chattr",
+                "btrfs",
+                "dd",
+                "fallocate",
+            },
+        )
+
+    def test_filesystem_specific_binaries_are_not_declared_as_always_required(self):
+        self.assertFalse(set(REQUIRED_BINARIES) & set(BTRFS_BINARIES))
+        self.assertFalse(set(REQUIRED_BINARIES) & set(NON_BTRFS_BINARIES))
+
+    def test_missing_binary_is_reported_with_its_name(self):
+        with mock.patch("swap_forge.core.subprocess.run") as subprocess_run:
+            subprocess_run.side_effect = FileNotFoundError
+
+            with self.assertRaises(MissingBinaryError) as caught:
+                run(["mkswap", "/swapfile"])
+
+        self.assertEqual(caught.exception.binary, "mkswap")
+
+
+class TestParseSizeToMib(unittest.TestCase):
+    def test_gibibytes(self):
+        for value in ("64G", "64g", "64GB", " 64G "):
+            with self.subTest(value=value):
+                self.assertEqual(parse_size_to_mib(value), 65536)
+
+    def test_mebibytes(self):
+        for value in ("2048M", "2048m", "2048MB"):
+            with self.subTest(value=value):
+                self.assertEqual(parse_size_to_mib(value), 2048)
+
+    def test_bare_number_is_mebibytes(self):
+        self.assertEqual(parse_size_to_mib("512"), 512)
+
+    def test_invalid_format(self):
+        for value in ("", "abc", "64T", "-5G", "6.5G"):
+            with self.subTest(value=value), self.assertRaises(ValueError):
+                parse_size_to_mib(value)
+
+    def test_unsupported_unit(self):
+        with self.assertRaises(ValueError):
+            parse_size_to_mib("64b")
+
+
+class TestSwapPathFor(unittest.TestCase):
+    def test_btrfs_uses_the_dedicated_subvolume_path(self):
+        self.assertEqual(swap_path_for("btrfs"), BTRFS_SWAP_PATH)
+
+    def test_other_filesystems_use_the_root_swapfile(self):
+        self.assertEqual(swap_path_for("ext4"), DEFAULT_SWAP_PATH)
+
+
+class TestGetSwapSize(unittest.TestCase):
+    def test_missing_file_is_zero(self):
+        self.assertEqual(get_swap_size(Path("/nonexistent/swapfile")), 0)
+
+    def test_reports_size_in_mebibytes(self):
+        with tempfile.TemporaryDirectory() as base:
+            path = Path(base) / "swapfile"
+            path.write_bytes(b"\0" * (3 * 1024 * 1024))
+
+            self.assertEqual(get_swap_size(path), 3)
+
+
+class TestSwapFstabLine(unittest.TestCase):
+    def test_line_shape(self):
+        self.assertEqual(
+            swap_fstab_line(Path("/swapfile")), "/swapfile none swap sw 0 0"
+        )
+
+
+class TestRemoveSwap(unittest.TestCase):
+    def test_drops_file_and_fstab_entry(self):
+        with tempfile.TemporaryDirectory() as base:
+            swapfile = Path(base) / "swapfile"
+            swapfile.write_bytes(b"\0")
+            fstab = Path(base) / "fstab"
+            fstab.write_text(
+                f"UUID=abc / ext4 defaults 0 1\n{swapfile} none swap sw 0 0\n"
+            )
+
+            with mock.patch("swap_forge.core.run"):
+                remove_swap(swapfile, fstab=fstab)
+
+            self.assertFalse(swapfile.exists())
+            self.assertEqual(fstab.read_text(), "UUID=abc / ext4 defaults 0 1\n")
+
+    def test_keeps_unrelated_fstab_entries(self):
+        with tempfile.TemporaryDirectory() as base:
+            swapfile = Path(base) / "swapfile"
+            fstab = Path(base) / "fstab"
+            fstab.write_text("/other none swap sw 0 0\n")
+
+            with mock.patch("swap_forge.core.run"):
+                remove_swap(swapfile, fstab=fstab)
+
+            self.assertEqual(fstab.read_text(), "/other none swap sw 0 0\n")
+
+    def test_missing_fstab_is_tolerated(self):
+        with tempfile.TemporaryDirectory() as base:
+            with mock.patch("swap_forge.core.run"):
+                remove_swap(Path(base) / "swapfile", fstab=Path(base) / "fstab")
+
+
+class TestCreateSwap(unittest.TestCase):
+    def test_non_btrfs_uses_fallocate_and_appends_to_fstab(self):
+        with tempfile.TemporaryDirectory() as base:
+            swapfile = Path(base) / "swapfile"
+            fstab = Path(base) / "fstab"
+            fstab.write_text("")
+
+            with mock.patch("swap_forge.core.run") as run:
+                create_swap(swapfile, 2048, "ext4", fstab=fstab)
+
+            commands = [call.args[0][0] for call in run.call_args_list]
+            self.assertEqual(commands, ["fallocate", "chmod", "mkswap", "swapon"])
+            self.assertEqual(fstab.read_text(), f"{swapfile} none swap sw 0 0\n")
+
+    def test_btrfs_disables_copy_on_write_and_uses_dd(self):
+        with tempfile.TemporaryDirectory() as base:
+            swapfile = Path(base) / "swap" / "swapfile"
+            fstab = Path(base) / "fstab"
+            fstab.write_text("")
+
+            with mock.patch("swap_forge.core.run") as run:
+                create_swap(swapfile, 1024, "btrfs", fstab=fstab)
+
+            commands = [call.args[0][0] for call in run.call_args_list]
+            self.assertEqual(
+                commands, ["chattr", "btrfs", "dd", "chmod", "mkswap", "swapon"]
+            )
+            self.assertTrue(swapfile.parent.is_dir())
+
+
+if __name__ == "__main__":
+    unittest.main()