Add lint coverage tests

pkg/lint/detect_project_test.go

@@ -29,6 +29,34 @@ func TestDetect_Good_ProjectMarkersAndFiles(t *testing.T) {
 	)
 }
 
+func TestDetect_Good_MarkerCoverage(t *testing.T) {
+	dir := t.TempDir()
+
+	files := map[string]string{
+		"go.mod":           "module example.com/test\n",
+		"composer.json":    "{}\n",
+		"package.json":     "{}\n",
+		"tsconfig.json":    "{}\n",
+		"requirements.txt": "ruff\n",
+		"pyproject.toml":   "[tool.ruff]\n",
+		"Cargo.toml":       "[package]\nname = \"test\"\n",
+		"Dockerfile.dev":   "FROM scratch\n",
+		"run.sh":           "#!/bin/sh\n",
+		"main.cpp":         "int main() { return 0; }\n",
+		"config.yaml":      "kind: Config\n",
+		"config.yml":       "kind: Config\n",
+	}
+
+	for name, content := range files {
+		require.NoError(t, os.WriteFile(filepath.Join(dir, name), []byte(content), 0o644))
+	}
+
+	assert.Equal(t,
+		[]string{"cpp", "dockerfile", "go", "js", "php", "python", "rust", "shell", "ts", "yaml"},
+		Detect(dir),
+	)
+}
+
 func TestDetectFromFiles_Good(t *testing.T) {
 	files := []string{
 		"main.go",
@@ -45,7 +73,7 @@ func TestDetectFromFiles_Good(t *testing.T) {
 	)
 }
 
-func TestDetect_MissingPathReturnsEmptySlice(t *testing.T) {
+func TestDetect_Bad_MissingPathReturnsEmptySlice(t *testing.T) {
 	assert.Equal(t, []string{}, Detect(filepath.Join(t.TempDir(), "missing")))
 }
 
@@ -57,3 +85,17 @@ func TestDetect_Good_SkipsHiddenRootDirectory(t *testing.T) {
 
 	assert.Equal(t, []string{}, Detect(hiddenDir))
 }
+
+func TestDetect_Ugly_SkipsNestedHiddenAndExcludedDirectories(t *testing.T) {
+	dir := t.TempDir()
+
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "root.go"), []byte("package main\n"), 0o644))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "vendor"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "vendor", "ignored.go"), []byte("package ignored\n"), 0o644))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, ".core"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, ".core", "ignored.go"), []byte("package ignored\n"), 0o644))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "services", ".generated"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "services", ".generated", "ignored.go"), []byte("package ignored\n"), 0o644))
+
+	assert.Equal(t, []string{"go"}, Detect(dir))
+}

pkg/lint/output_test.go

@@ -62,3 +62,26 @@ func TestResolveRunOutputFormat_Good_ExplicitOutputBypassesConfigLoading(t *test
 	require.NoError(t, err)
 	assert.Equal(t, "sarif", format)
 }
+
+func TestResolveRunOutputFormat_Bad_BrokenConfig(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, ".core"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, ".core", "lint.yaml"), []byte("{not: yaml"), 0o644))
+
+	_, err := ResolveRunOutputFormat(RunInput{
+		Path: dir,
+	})
+	assert.Error(t, err)
+}
+
+func TestResolveRunOutputFormat_Ugly_MissingSchedule(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, ".core"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, ".core", "lint.yaml"), []byte("output: text\n"), 0o644))
+
+	_, err := ResolveRunOutputFormat(RunInput{
+		Path:     dir,
+		Schedule: "nightly",
+	})
+	assert.Error(t, err)
+}

pkg/lint/report_test.go

@@ -58,6 +58,19 @@ func TestSummarise_Good_Empty(t *testing.T) {
 	assert.Empty(t, summary.BySeverity)
 }
 
+func TestSummarise_Bad_BlankSeverityDefaultsToWarning(t *testing.T) {
+	summary := Summarise([]Finding{
+		{Severity: ""},
+		{Severity: "info"},
+	})
+
+	assert.Equal(t, 2, summary.Total)
+	assert.Equal(t, 1, summary.Warnings)
+	assert.Equal(t, 1, summary.Info)
+	assert.Equal(t, 0, summary.Errors)
+	assert.True(t, summary.Passed)
+}
+
 func TestWriteJSON_Good_Roundtrip(t *testing.T) {
 	findings := sampleFindings()
 	var buf bytes.Buffer
@@ -116,6 +129,11 @@ func TestWriteJSONL_Good_Empty(t *testing.T) {
 	assert.Empty(t, buf.String())
 }
 
+func TestWriteJSONL_Bad_PropagatesWriterErrors(t *testing.T) {
+	err := WriteJSONL(failingWriter{}, sampleFindings())
+	require.Error(t, err)
+}
+
 func TestWriteText_Good(t *testing.T) {
 	findings := sampleFindings()
 	var buf bytes.Buffer

pkg/lint/scanner_test.go

@@ -29,6 +29,9 @@ func TestDetectLanguage_Good(t *testing.T) {
 		{"noextension", ""},
 		{"file.py", "python"},
 		{"Dockerfile", "dockerfile"},
+		{"services/Dockerfile.prod", "dockerfile"},
+		{"configs/settings.yaml", "yaml"},
+		{"configs/settings.yml", "yaml"},
 	}
 
 	for _, tt := range tests {
@@ -39,6 +42,15 @@ func TestDetectLanguage_Good(t *testing.T) {
 	}
 }
 
+func TestDetectLanguage_Bad_UnknownExtension(t *testing.T) {
+	assert.Equal(t, "", DetectLanguage("notes.txt"))
+	assert.Equal(t, "", DetectLanguage("README"))
+}
+
+func TestDetectLanguage_Ugly_DockerfileVariant(t *testing.T) {
+	assert.Equal(t, "dockerfile", DetectLanguage("nested/Dockerfile.test"))
+}
+
 func TestScanDir_Good_FindsMatches(t *testing.T) {
 	dir := t.TempDir()
 
@@ -209,6 +221,58 @@ func TestScanFile_Good_Python(t *testing.T) {
 	assert.Equal(t, "python", DetectLanguage(file))
 }
 
+func TestScanFile_Bad_NoMatchingLanguageRules(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "app.go")
+	err := os.WriteFile(file, []byte("package main\n"), 0o644)
+	require.NoError(t, err)
+
+	rules := []Rule{
+		{
+			ID:        "php-only",
+			Title:     "PHP TODO",
+			Severity:  "low",
+			Languages: []string{"php"},
+			Pattern:   `TODO`,
+			Fix:       "Remove TODO",
+			Detection: "regex",
+		},
+	}
+
+	s, err := NewScanner(rules)
+	require.NoError(t, err)
+
+	findings, err := s.ScanFile(file)
+	require.NoError(t, err)
+	assert.Empty(t, findings)
+}
+
+func TestScanFile_Ugly_UnsupportedExtension(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "notes.txt")
+	err := os.WriteFile(file, []byte("TODO: this is not a recognised source file\n"), 0o644)
+	require.NoError(t, err)
+
+	rules := []Rule{
+		{
+			ID:        "go-only",
+			Title:     "Go TODO",
+			Severity:  "low",
+			Languages: []string{"go"},
+			Pattern:   `TODO`,
+			Fix:       "Remove TODO",
+			Detection: "regex",
+		},
+	}
+
+	s, err := NewScanner(rules)
+	require.NoError(t, err)
+
+	findings, err := s.ScanFile(file)
+	require.NoError(t, err)
+	assert.Nil(t, findings)
+}
+
 func TestScanDir_Good_Subdirectories(t *testing.T) {
 	dir := t.TempDir()