test(release): cover automated release preparation

internal/releaseprep/releaseprep_test.go

@@ -0,0 +1,63 @@
+package releaseprep
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+)
+
+type PrepareSuite struct {
+	suite.Suite
+	rootDir string
+}
+
+func TestPrepareSuite(t *testing.T) {
+	suite.Run(t, new(PrepareSuite))
+}
+
+func (s *PrepareSuite) SetupTest() {
+	s.rootDir = s.T().TempDir()
+	versionDir := filepath.Join(s.rootDir, "internal", "homesick", "version")
+	require.NoError(s.T(), os.MkdirAll(versionDir, 0o755))
+
+	require.NoError(s.T(), os.WriteFile(
+		filepath.Join(versionDir, "version.go"),
+		[]byte("package version\n\nconst String = \"1.1.6\"\n"),
+		0o644,
+	))
+
+	require.NoError(s.T(), os.WriteFile(
+		filepath.Join(s.rootDir, "changelog.md"),
+		[]byte("# Changelog\n\n## [Unreleased]\n\n### Added\n\n- New thing.\n\n### Fixed\n\n- Old thing.\n\n## [1.1.6] - 2017-12-20\n\n### Fixed\n\n- Historical note.\n"),
+		0o644,
+	))
+}
+
+func (s *PrepareSuite) TestPrepare_UpdatesVersionAndPromotesUnreleasedNotes() {
+	err := Prepare(s.rootDir, "v1.1.7", "2026-03-20")
+
+	require.NoError(s.T(), err)
+
+	versionBytes, err := os.ReadFile(filepath.Join(s.rootDir, "internal", "homesick", "version", "version.go"))
+	require.NoError(s.T(), err)
+	require.Equal(s.T(), "package version\n\nconst String = \"1.1.7\"\n", string(versionBytes))
+
+	changelogBytes, err := os.ReadFile(filepath.Join(s.rootDir, "changelog.md"))
+	require.NoError(s.T(), err)
+	require.Equal(s.T(), "# Changelog\n\n## [Unreleased]\n\n## [1.1.7] - 2026-03-20\n\n### Added\n\n- New thing.\n\n### Fixed\n\n- Old thing.\n\n## [1.1.6] - 2017-12-20\n\n### Fixed\n\n- Historical note.\n", string(changelogBytes))
+}
+
+func (s *PrepareSuite) TestPrepare_ReturnsErrorWhenUnreleasedSectionMissing() {
+	require.NoError(s.T(), os.WriteFile(
+		filepath.Join(s.rootDir, "changelog.md"),
+		[]byte("# Changelog\n\n## [1.1.6] - 2017-12-20\n"),
+		0o644,
+	))
+
+	err := Prepare(s.rootDir, "1.1.7", "2026-03-20")
+
+	require.ErrorContains(s.T(), err, "unreleased section")
+}