From a82e98d775112155dfe72f78c977dee21472ddbb Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Mon, 2 Mar 2026 19:55:44 +0100
Subject: [PATCH 1/9] Move git-check-assertions to bin/

---
 git-check-assertions => bin/git-check-assertions | 0
 default.nix                                      | 6 +++---
 test.bats                                        | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)
 rename git-check-assertions => bin/git-check-assertions (100%)

diff --git a/git-check-assertions b/bin/git-check-assertions
similarity index 100%
rename from git-check-assertions
rename to bin/git-check-assertions
diff --git a/default.nix b/default.nix
index 4dde1cf..8653ca0 100644
--- a/default.nix
+++ b/default.nix
@@ -20,7 +20,7 @@ resholve.mkDerivation {
   src = fs.toSource {
     root = ./.;
     fileset = fs.unions [
-      ./git-check-assertions
+      ./bin/git-check-assertions
       ./test.bats
     ];
   };
@@ -37,7 +37,7 @@ resholve.mkDerivation {
 
   checkPhase = ''
     runHook preCheck
-    shellcheck git-check-assertions test.bats
+    shellcheck bin/git-check-assertions test.bats
     git init
     git config user.email test
     git config user.name test
@@ -52,7 +52,7 @@ resholve.mkDerivation {
   installPhase = ''
     runHook preInstall
     mkdir -p $out/bin
-    cp $src/git-check-assertions $out/bin/git-check-assertions
+    cp $src/bin/git-check-assertions $out/bin/git-check-assertions
     runHook postInstall
   '';
 
diff --git a/test.bats b/test.bats
index 48965fd..96bf6d5 100755
--- a/test.bats
+++ b/test.bats
@@ -2,7 +2,7 @@
 
 setup() {
   DIR="$( cd "$( dirname "$BATS_TEST_FILENAME" )" >/dev/null 2>&1 && pwd )"
-  PATH="$DIR:$PATH"
+  PATH="$DIR/bin:$PATH"
 }
 
 @test "can run" {

From 653a1b67bc29afdf622bf7dddecadbf464907c79 Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Mon, 2 Mar 2026 19:57:44 +0100
Subject: [PATCH 2/9] Move test.bats to test/git-check-assertions.bats

---
 default.nix                                 | 6 +++---
 test.bats => test/git-check-assertions.bats | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)
 rename test.bats => test/git-check-assertions.bats (85%)

diff --git a/default.nix b/default.nix
index 8653ca0..ecb1f69 100644
--- a/default.nix
+++ b/default.nix
@@ -21,7 +21,7 @@ resholve.mkDerivation {
     root = ./.;
     fileset = fs.unions [
       ./bin/git-check-assertions
-      ./test.bats
+      ./test/git-check-assertions.bats
     ];
   };
 
@@ -37,13 +37,13 @@ resholve.mkDerivation {
 
   checkPhase = ''
     runHook preCheck
-    shellcheck bin/git-check-assertions test.bats
+    shellcheck bin/git-check-assertions test/git-check-assertions.bats
     git init
     git config user.email test
     git config user.name test
     git checkout -b main
     git commit --allow-empty -m "initial"
-    ./test.bats
+    ./test/git-check-assertions.bats
     runHook postCheck
   '';
 
diff --git a/test.bats b/test/git-check-assertions.bats
similarity index 85%
rename from test.bats
rename to test/git-check-assertions.bats
index 96bf6d5..8371aea 100755
--- a/test.bats
+++ b/test/git-check-assertions.bats
@@ -2,7 +2,7 @@
 
 setup() {
   DIR="$( cd "$( dirname "$BATS_TEST_FILENAME" )" >/dev/null 2>&1 && pwd )"
-  PATH="$DIR/bin:$PATH"
+  PATH="$DIR/../bin:$PATH"
 }
 
 @test "can run" {

From e48e27fb523189d1652d53a8a78c7a5e976ea6b9 Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Mon, 2 Mar 2026 20:06:53 +0100
Subject: [PATCH 3/9] Add helper modules for bats

According to these instructions:
https://bats-core.readthedocs.io/en/stable/tutorial.html#quick-installation
---
 .gitmodules                    | 9 +++++++++
 README.md                      | 6 ++++++
 default.nix                    | 4 ++--
 test/git-check-assertions.bats | 6 +++++-
 test/test_helper/bats-assert   | 1 +
 test/test_helper/bats-file     | 1 +
 test/test_helper/bats-support  | 1 +
 7 files changed, 25 insertions(+), 3 deletions(-)
 create mode 100644 .gitmodules
 create mode 160000 test/test_helper/bats-assert
 create mode 160000 test/test_helper/bats-file
 create mode 160000 test/test_helper/bats-support

diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..9ec278b
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,9 @@
+[submodule "test/test_helper/bats-support"]
+	path = test/test_helper/bats-support
+	url = https://github.com/bats-core/bats-support.git
+[submodule "test/test_helper/bats-assert"]
+	path = test/test_helper/bats-assert
+	url = https://github.com/bats-core/bats-assert.git
+[submodule "test/test_helper/bats-file"]
+	path = test/test_helper/bats-file
+	url = https://github.com/bats-core/bats-file.git
diff --git a/README.md b/README.md
index 0b302ca..01c4cb6 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,12 @@ You include a small bash script inside your commit messages, and `git-check-asse
 
 ⚠️ Only run this on repositories and branches that you trust, since the `bash` scripts in the commit messages can do whatever they want.
 
+## Building
+
+```bash
+nix build .?submodules=1
+```
+
 ## Examples of commit messages
 
 Assert that a commit builds:
diff --git a/default.nix b/default.nix
index ecb1f69..47212a6 100644
--- a/default.nix
+++ b/default.nix
@@ -20,8 +20,8 @@ resholve.mkDerivation {
   src = fs.toSource {
     root = ./.;
     fileset = fs.unions [
-      ./bin/git-check-assertions
-      ./test/git-check-assertions.bats
+      ./bin
+      ./test
     ];
   };
 
diff --git a/test/git-check-assertions.bats b/test/git-check-assertions.bats
index 8371aea..8de6cf7 100755
--- a/test/git-check-assertions.bats
+++ b/test/git-check-assertions.bats
@@ -1,10 +1,14 @@
 #!/usr/bin/env bats
 
 setup() {
+  load 'test_helper/bats-support/load'
+  load 'test_helper/bats-assert/load'
+
   DIR="$( cd "$( dirname "$BATS_TEST_FILENAME" )" >/dev/null 2>&1 && pwd )"
   PATH="$DIR/../bin:$PATH"
 }
 
 @test "can run" {
-  git-check-assertions
+  run git-check-assertions
+  assert_success
 }
diff --git a/test/test_helper/bats-assert b/test/test_helper/bats-assert
new file mode 160000
index 0000000..697471b
--- /dev/null
+++ b/test/test_helper/bats-assert
@@ -0,0 +1 @@
+Subproject commit 697471b7a89d3ab38571f38c6c7c4b460d1f5e35
diff --git a/test/test_helper/bats-file b/test/test_helper/bats-file
new file mode 160000
index 0000000..6bee58b
--- /dev/null
+++ b/test/test_helper/bats-file
@@ -0,0 +1 @@
+Subproject commit 6bee58bec7c2f4aed1a7425ccd4bdc42b4a84599
diff --git a/test/test_helper/bats-support b/test/test_helper/bats-support
new file mode 160000
index 0000000..0954abb
--- /dev/null
+++ b/test/test_helper/bats-support
@@ -0,0 +1 @@
+Subproject commit 0954abb9925cad550424cebca2b99255d4eabe96

From f5f05c0a9ef4814e5f2bd279f64ef5c71ea8fa52 Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Mon, 2 Mar 2026 20:18:09 +0100
Subject: [PATCH 4/9] Set up the git repository in the bats file instead

---
 default.nix                    | 5 -----
 test/git-check-assertions.bats | 6 ++++++
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/default.nix b/default.nix
index 47212a6..e159ff1 100644
--- a/default.nix
+++ b/default.nix
@@ -38,11 +38,6 @@ resholve.mkDerivation {
   checkPhase = ''
     runHook preCheck
     shellcheck bin/git-check-assertions test/git-check-assertions.bats
-    git init
-    git config user.email test
-    git config user.name test
-    git checkout -b main
-    git commit --allow-empty -m "initial"
     ./test/git-check-assertions.bats
     runHook postCheck
   '';
diff --git a/test/git-check-assertions.bats b/test/git-check-assertions.bats
index 8de6cf7..f4b27e8 100755
--- a/test/git-check-assertions.bats
+++ b/test/git-check-assertions.bats
@@ -6,9 +6,15 @@ setup() {
 
   DIR="$( cd "$( dirname "$BATS_TEST_FILENAME" )" >/dev/null 2>&1 && pwd )"
   PATH="$DIR/../bin:$PATH"
+
+  git init
+  git config user.email "john.doe@example.com"
+  git config user.name "John Doe"
+  git checkout -b main
 }
 
 @test "can run" {
+  git commit --allow-empty -m "Initial"
   run git-check-assertions
   assert_success
 }

From 769d7da9b21fc58bf82aebb3b1d9d5714c479ad8 Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Mon, 2 Mar 2026 20:25:46 +0100
Subject: [PATCH 5/9] Use git init to immediately create the correct branch

---
 test/git-check-assertions.bats | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/test/git-check-assertions.bats b/test/git-check-assertions.bats
index f4b27e8..9c5006f 100755
--- a/test/git-check-assertions.bats
+++ b/test/git-check-assertions.bats
@@ -7,10 +7,9 @@ setup() {
   DIR="$( cd "$( dirname "$BATS_TEST_FILENAME" )" >/dev/null 2>&1 && pwd )"
   PATH="$DIR/../bin:$PATH"
 
-  git init
+  git init -b main
   git config user.email "john.doe@example.com"
   git config user.name "John Doe"
-  git checkout -b main
 }
 
 @test "can run" {

From 5dbb6aea8f5ceaff9f6ce3f6fd1099cb6e46ff6d Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Mon, 2 Mar 2026 20:53:52 +0100
Subject: [PATCH 6/9] Set up shfmt

---
 bin/git-check-assertions       | 11 +++++++----
 default.nix                    |  4 ++++
 flake.nix                      |  5 ++++-
 test/git-check-assertions.bats |  2 +-
 4 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/bin/git-check-assertions b/bin/git-check-assertions
index a023370..f7fe936 100755
--- a/bin/git-check-assertions
+++ b/bin/git-check-assertions
@@ -25,7 +25,10 @@
 set -euo pipefail
 
 assert_fails() {
-  ! "$@" || { echo "Expected command to fail, but it succeeded."; exit 1; }
+  ! "$@" || {
+    echo "Expected command to fail, but it succeeded."
+    exit 1
+  }
 }
 export -f assert_fails
 
@@ -42,9 +45,9 @@ for commit_hash in "${commits[@]}"; do
   git -c advice.detachedHead=false checkout -q "$commit_hash"
   commit_msg="$(git log -1 --format=%B "$commit_hash")"
   # shellcheck disable=SC2016
-  block="$(printf '%s\n' "$commit_msg" \
-    | sed -n '/^```git-check-assertions[[:space:]]*$/,/^```[[:space:]]*$/p' \
-    | sed '1d;$d')"
+  block="$(printf '%s\n' "$commit_msg" |
+    sed -n '/^```git-check-assertions[[:space:]]*$/,/^```[[:space:]]*$/p' |
+    sed '1d;$d')"
   if [ -n "$block" ]; then
     echo "git-check-assertions block in $commit_hash:"
     printf '%s\n' "$block" | sed 's/^/> /'
diff --git a/default.nix b/default.nix
index e159ff1..a956baf 100644
--- a/default.nix
+++ b/default.nix
@@ -8,6 +8,7 @@
   shellcheck-minimal,
   gitMinimal,
   resholve,
+  shfmt,
 }:
 
 let
@@ -20,6 +21,7 @@ resholve.mkDerivation {
   src = fs.toSource {
     root = ./.;
     fileset = fs.unions [
+      ./.editorconfig
       ./bin
       ./test
     ];
@@ -33,11 +35,13 @@ resholve.mkDerivation {
     shellcheck-minimal
     bats
     gitMinimal
+    shfmt
   ];
 
   checkPhase = ''
     runHook preCheck
     shellcheck bin/git-check-assertions test/git-check-assertions.bats
+    shfmt -d bin/git-check-assertions test/git-check-assertions.bats
     ./test/git-check-assertions.bats
     runHook postCheck
   '';
diff --git a/flake.nix b/flake.nix
index 55f8f46..60198ee 100644
--- a/flake.nix
+++ b/flake.nix
@@ -16,7 +16,10 @@
       {
         packages.default = pkgs.callPackage ./default.nix { };
         devShells.default = pkgs.mkShell {
-          packages = with pkgs; [ bats ];
+          packages = with pkgs; [
+            bats
+            shfmt
+          ];
         };
       }
     );
diff --git a/test/git-check-assertions.bats b/test/git-check-assertions.bats
index 9c5006f..4ad07e9 100755
--- a/test/git-check-assertions.bats
+++ b/test/git-check-assertions.bats
@@ -4,7 +4,7 @@ setup() {
   load 'test_helper/bats-support/load'
   load 'test_helper/bats-assert/load'
 
-  DIR="$( cd "$( dirname "$BATS_TEST_FILENAME" )" >/dev/null 2>&1 && pwd )"
+  DIR="$(cd "$(dirname "$BATS_TEST_FILENAME")" >/dev/null 2>&1 && pwd)"
   PATH="$DIR/../bin:$PATH"
 
   git init -b main

From f4cdb276c39eb0eea0b4b8ec12b776d1fcc25e06 Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Mon, 2 Mar 2026 20:26:02 +0100
Subject: [PATCH 7/9] Add some initial tests

---
 test/git-check-assertions.bats | 99 +++++++++++++++++++++++++++++++++-
 1 file changed, 97 insertions(+), 2 deletions(-)

diff --git a/test/git-check-assertions.bats b/test/git-check-assertions.bats
index 4ad07e9..0b0b0e1 100755
--- a/test/git-check-assertions.bats
+++ b/test/git-check-assertions.bats
@@ -1,19 +1,114 @@
 #!/usr/bin/env bats
 
 setup() {
+  set -euo pipefail
+
   load 'test_helper/bats-support/load'
   load 'test_helper/bats-assert/load'
+  load 'test_helper/bats-file/load'
 
   DIR="$(cd "$(dirname "$BATS_TEST_FILENAME")" >/dev/null 2>&1 && pwd)"
   PATH="$DIR/../bin:$PATH"
 
+  mkdir "$BATS_TEST_TMPDIR/repo"
+  cd "$BATS_TEST_TMPDIR/repo"
   git init -b main
   git config user.email "john.doe@example.com"
   git config user.name "John Doe"
+  touch readme
+  git add readme
+  git commit -m "initial"
 }
 
-@test "can run" {
-  git commit --allow-empty -m "Initial"
+commit_with_assertion() {
+  git commit --allow-empty -F - <<-EOF
+		test
+
+		\`\`\`git-check-assertions
+		$1
+		\`\`\`
+	EOF
+}
+
+@test "should not run any assertion blocks when on main" {
+  commit_with_assertion "touch ../test"
+
   run git-check-assertions
+
+  assert_success
+  assert_file_not_exists ../test
+}
+
+@test "should not run any assertion blocks from main when on a feature branch" {
+  commit_with_assertion "touch ../test"
+  git checkout -b feature
+  git commit --allow-empty -m "feature"
+
+  run git-check-assertions
+
+  assert_success
+  assert_file_not_exists ../test
+}
+
+@test "should run all succeeding assertion blocks on the feature branch and finally return to the original branch" {
+  git checkout -b feature
+  commit_with_assertion "touch ../test1"
+  commit_with_assertion "touch ../test2"
+
+  run git-check-assertions
+
+  assert_success
+  assert_file_exists ../test1
+  assert_file_exists ../test2
+  run git symbolic-ref --short HEAD
+  assert_output "feature"
+}
+
+@test "should stop at the first failing assertion block and return to the original branch" {
+  git checkout -b feature
+  commit_with_assertion "touch ../test1 && exit 3"
+  commit_with_assertion "touch ../test2"
+
+  run git-check-assertions
+
+  assert_failure
+  assert_file_exists ../test1
+  assert_file_not_exists ../test2
+  run git symbolic-ref --short HEAD
+  assert_output "feature"
+}
+
+@test "should restore worktree when finished" {
+  git checkout -b feature
+  commit_with_assertion 'echo blah >> readme'
+
+  run git-check-assertions
+
+  assert_success
+  assert_size_zero readme
+}
+
+@test "should restore worktree between commits" {
+  git checkout -b feature
+  commit_with_assertion 'echo blah >> readme'
+  commit_with_assertion 'cp readme ../test'
+
+  run git-check-assertions
+
+  assert_success
+  assert_size_zero ../test
+}
+
+@test "assertions should run against the version of the code inside of the commit" {
+  git checkout -b feature
+  echo commit1 >readme
+  git add readme
+  commit_with_assertion 'grep commit1 readme'
+  echo commit2 >readme
+  git add readme
+  commit_with_assertion 'grep commit2 readme'
+
+  run git-check-assertions
+
   assert_success
 }

From e9c8e3b35eca32b1d93be4009e9308b99a9b2380 Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Tue, 3 Mar 2026 07:07:28 +0100
Subject: [PATCH 8/9] Use bats.withLibraries instead of submodules

---
 .gitmodules                    |  9 ---------
 README.md                      |  2 +-
 default.nix                    |  6 +++++-
 flake.nix                      | 10 +++++++---
 test/git-check-assertions.bats |  6 +++---
 test/test_helper/bats-assert   |  1 -
 test/test_helper/bats-file     |  1 -
 test/test_helper/bats-support  |  1 -
 8 files changed, 16 insertions(+), 20 deletions(-)
 delete mode 100644 .gitmodules
 delete mode 160000 test/test_helper/bats-assert
 delete mode 160000 test/test_helper/bats-file
 delete mode 160000 test/test_helper/bats-support

diff --git a/.gitmodules b/.gitmodules
deleted file mode 100644
index 9ec278b..0000000
--- a/.gitmodules
+++ /dev/null
@@ -1,9 +0,0 @@
-[submodule "test/test_helper/bats-support"]
-	path = test/test_helper/bats-support
-	url = https://github.com/bats-core/bats-support.git
-[submodule "test/test_helper/bats-assert"]
-	path = test/test_helper/bats-assert
-	url = https://github.com/bats-core/bats-assert.git
-[submodule "test/test_helper/bats-file"]
-	path = test/test_helper/bats-file
-	url = https://github.com/bats-core/bats-file.git
diff --git a/README.md b/README.md
index 01c4cb6..79ff8de 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ You include a small bash script inside your commit messages, and `git-check-asse
 ## Building
 
 ```bash
-nix build .?submodules=1
+nix build .
 ```
 
 ## Examples of commit messages
diff --git a/default.nix b/default.nix
index a956baf..d8055a8 100644
--- a/default.nix
+++ b/default.nix
@@ -33,7 +33,11 @@ resholve.mkDerivation {
 
   nativeCheckInputs = [
     shellcheck-minimal
-    bats
+    (bats.withLibraries (p: [
+      p.bats-assert
+      p.bats-support
+      p.bats-file
+    ]))
     gitMinimal
     shfmt
   ];
diff --git a/flake.nix b/flake.nix
index 60198ee..e82af69 100644
--- a/flake.nix
+++ b/flake.nix
@@ -16,9 +16,13 @@
       {
         packages.default = pkgs.callPackage ./default.nix { };
         devShells.default = pkgs.mkShell {
-          packages = with pkgs; [
-            bats
-            shfmt
+          packages = [
+            (pkgs.bats.withLibraries (p: [
+              p.bats-assert
+              p.bats-support
+              p.bats-file
+            ]))
+            pkgs.shfmt
           ];
         };
       }
diff --git a/test/git-check-assertions.bats b/test/git-check-assertions.bats
index 0b0b0e1..f58c3ea 100755
--- a/test/git-check-assertions.bats
+++ b/test/git-check-assertions.bats
@@ -3,9 +3,9 @@
 setup() {
   set -euo pipefail
 
-  load 'test_helper/bats-support/load'
-  load 'test_helper/bats-assert/load'
-  load 'test_helper/bats-file/load'
+  bats_load_library bats-support
+  bats_load_library bats-assert
+  bats_load_library bats-file
 
   DIR="$(cd "$(dirname "$BATS_TEST_FILENAME")" >/dev/null 2>&1 && pwd)"
   PATH="$DIR/../bin:$PATH"
diff --git a/test/test_helper/bats-assert b/test/test_helper/bats-assert
deleted file mode 160000
index 697471b..0000000
--- a/test/test_helper/bats-assert
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 697471b7a89d3ab38571f38c6c7c4b460d1f5e35
diff --git a/test/test_helper/bats-file b/test/test_helper/bats-file
deleted file mode 160000
index 6bee58b..0000000
--- a/test/test_helper/bats-file
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 6bee58bec7c2f4aed1a7425ccd4bdc42b4a84599
diff --git a/test/test_helper/bats-support b/test/test_helper/bats-support
deleted file mode 160000
index 0954abb..0000000
--- a/test/test_helper/bats-support
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 0954abb9925cad550424cebca2b99255d4eabe96

From 1fb1fcc4fa0c07197ccb1e64cc1030859c013688 Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Tue, 3 Mar 2026 07:15:06 +0100
Subject: [PATCH 9/9] Add installation instructions

---
 README.md | 37 ++++++++++++++++++++++++++++++++++---
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 79ff8de..f0479cd 100644
--- a/README.md
+++ b/README.md
@@ -13,10 +13,41 @@ You include a small bash script inside your commit messages, and `git-check-asse
 
 ⚠️ Only run this on repositories and branches that you trust, since the `bash` scripts in the commit messages can do whatever they want.
 
-## Building
+## Installation
 
-```bash
-nix build .
+On most systems, clone this repository and add the `bin` directory to your `PATH`.
+
+If you use Nix with flakes, you can simply add it to your program's devshell instead:
+
+```diff
+@@ -2,12 +2,18 @@
+   inputs = {
+     nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+     flake-utils.url = "github:numtide/flake-utils";
++    git-check-assertions = {
++      url = "git+https://codeberg.org/svenvanheugten/git-check-assertions.git?ref=main";
++      inputs.nixpkgs.follows = "nixpkgs";
++      inputs.flake-utils.follows = "flake-utils";
++    };
+   };
+   outputs =
+     {
+       self,
+       nixpkgs,
+       flake-utils,
++      git-check-assertions,
+     }:
+     flake-utils.lib.eachDefaultSystem (
+       system:
+@@ -17,7 +23,10 @@
+       {
+         packages.default = pkgs.callPackage ./default.nix { };
+         devShells.default = pkgs.mkShell {
+-          packages = [ ];
++          packages = [ git-check-assertions.packages.${system}.default ];
+         };
+       }
+     )
 ```
 
 ## Examples of commit messages