Add some initial tests

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
 }