Increase test coverage

Author: axw

scraper/scraperhelper/controller_test.go

@@ -771,6 +771,62 @@ func addLogsScraper(t component.Type, sc scraper.Logs) ControllerOption {
 	return AddFactoryWithConfig(f, nil)
 }
 
+func TestAddScraper(t *testing.T) {
+	t.Parallel()
+
+	// AddScraper is deprecated but must continue to work identically to AddMetricsScraper.
+	scp, err := scraper.NewMetrics(func(context.Context) (pmetric.Metrics, error) {
+		return pmetric.NewMetrics(), nil
+	})
+	require.NoError(t, err)
+
+	recv, err := NewMetricsController(
+		newTestNoDelaySettings(),
+		receivertest.NewNopSettings(receivertest.NopType),
+		new(consumertest.MetricsSink),
+		AddScraper(component.MustNewType("scraper"), scp), //nolint:staticcheck
+	)
+	require.NoError(t, err)
+	require.NoError(t, recv.Start(context.Background(), componenttest.NewNopHost()))
+	require.NoError(t, recv.Shutdown(context.Background()))
+}
+
+func TestNewLogsControllerCreateLogsError(t *testing.T) {
+	t.Parallel()
+
+	createErr := errors.New("create logs failed")
+	f := scraper.NewFactory(component.MustNewType("scraper"), nil,
+		scraper.WithLogs(func(context.Context, scraper.Settings, component.Config) (scraper.Logs, error) {
+			return nil, createErr
+		}, component.StabilityLevelAlpha))
+
+	_, err := NewLogsController(
+		newTestNoDelaySettings(),
+		receivertest.NewNopSettings(receivertest.NopType),
+		new(consumertest.LogsSink),
+		AddFactoryWithConfig(f, nil),
+	)
+	require.ErrorIs(t, err, createErr)
+}
+
+func TestNewMetricsControllerCreateMetricsError(t *testing.T) {
+	t.Parallel()
+
+	createErr := errors.New("create metrics failed")
+	f := scraper.NewFactory(component.MustNewType("scraper"), nil,
+		scraper.WithMetrics(func(context.Context, scraper.Settings, component.Config) (scraper.Metrics, error) {
+			return nil, createErr
+		}, component.StabilityLevelAlpha))
+
+	_, err := NewMetricsController(
+		newTestNoDelaySettings(),
+		receivertest.NewNopSettings(receivertest.NopType),
+		new(consumertest.MetricsSink),
+		AddFactoryWithConfig(f, nil),
+	)
+	require.ErrorIs(t, err, createErr)
+}
+
 func TestNewDefaultControllerConfig(t *testing.T) {
 	controllerConfig := NewDefaultControllerConfig()
 	intControllerConfig := controller.NewDefaultControllerConfig()

scraper/scraperhelper/internal/controller/controller_test.go

@@ -17,6 +17,7 @@ import (
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/extension/xextension/extensionscrapercontroller"
 	"go.opentelemetry.io/collector/receiver/receivertest"
 	"go.opentelemetry.io/collector/scraper/scraperhelper/internal/testhelper"
 )
@@ -27,6 +28,17 @@ type mockScraper struct {
 	component.ShutdownFunc
 }
 
+// nilDeregControllerExtension returns a nil DeregisterFunc, violating the
+// ControllerExtension contract. Used to exercise the defensive nil guard in teardown.
+type nilDeregControllerExtension struct {
+	component.StartFunc
+	component.ShutdownFunc
+}
+
+func (e *nilDeregControllerExtension) RegisterScraper(_ context.Context, _ extensionscrapercontroller.ScrapeFunc) (extensionscrapercontroller.DeregisterFunc, error) {
+	return nil, nil
+}
+
 func nopScrapeFunc(context.Context, *Controller[component.Component]) error {
 	return nil
 }
@@ -334,6 +346,10 @@ func TestStartExtensionRegistersAndDeregisters(t *testing.T) {
 
 	require.NoError(t, ctrl.Shutdown(context.Background()))
 	assert.True(t, mockExt.Deregistered.Load())
+
+	// Calling Scrape after deregistration must return nil without invoking
+	// the scrape function (exercises the Deregistered early-exit path).
+	require.NoError(t, mockExt.Scrape(context.Background()))
 }
 
 func TestStartExtensionCallbackInvokesScrapeFunc(t *testing.T) {
@@ -659,6 +675,25 @@ func TestShutdownDeregisterError(t *testing.T) {
 	assert.True(t, mockExt.Deregistered.Load())
 }
 
+func TestTeardownNilDeregFunc(t *testing.T) {
+	t.Parallel()
+
+	// An extension that returns (nil, nil) from RegisterScraper, violating
+	// the contract. The controller must not panic when encountering a nil
+	// DeregisterFunc in the deregFuncs slice.
+	extID := component.MustNewID("nilext")
+	cfg := &ControllerConfig{
+		Controllers: []component.ID{extID},
+	}
+	ctrl := newTestController(t, cfg, nil)
+
+	host := &testhelper.MockHost{Extensions: map[component.ID]component.Component{
+		extID: &nilDeregControllerExtension{},
+	}}
+	require.NoError(t, ctrl.Start(context.Background(), host))
+	require.NoError(t, ctrl.Shutdown(context.Background()))
+}
+
 func TestStartMultipleExtensions(t *testing.T) {
 	t.Parallel()