Deprecate component_test in favor of metadatatest (#11812)

The main idea behind this is that the test helpers were generated in the
main package, hard to find and understand and also impossible to use
outside the main package, see the
[service/internal/proctelemetry/process_telemetry_test.go](https://github.com/open-telemetry/opentelemetry-collector/compare/main...bogdandrutu:opentelemetry-collector:dep-comp-test?expand=1#diff-ed642eb1c968a9308a07e87292f77af1e0830a7af2d87111c5abacde4fc87446).

Signed-off-by: Bogdan Drutu <[email protected]>

Author: bogdandrutu

.chloggen/dep-comp-test.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: deprecation
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: mdatagen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Deprecate component_test in favor of metadatatest
+
+# One or more tracking issues or pull requests related to the change
+issues: [11812]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

cmd/mdatagen/internal/command.go

@@ -78,6 +78,10 @@ func run(ymlPath string) error {
 	if err = os.MkdirAll(codeDir, 0o700); err != nil {
 		return fmt.Errorf("unable to create output directory %q: %w", codeDir, err)
 	}
+	testDir := filepath.Join(ymlDir, "internal", md.GeneratedPackageName+"test")
+	if err = os.MkdirAll(testDir, 0o700); err != nil {
+		return fmt.Errorf("unable to create output test directory %q: %w", codeDir, err)
+	}
 	if md.Status != nil {
 		if md.Status.Class != "cmd" && md.Status.Class != "pkg" && !md.Status.NotComponent {
 			if err = generateFile(filepath.Join(tmplDir, "status.go.tmpl"),
@@ -114,6 +118,8 @@ func run(ymlPath string) error {
 		}
 		toGenerate[filepath.Join(tmplDir, "telemetry.go.tmpl")] = filepath.Join(codeDir, "generated_telemetry.go")
 		toGenerate[filepath.Join(tmplDir, "telemetry_test.go.tmpl")] = filepath.Join(codeDir, "generated_telemetry_test.go")
+		toGenerate[filepath.Join(tmplDir, "telemetrytest.go.tmpl")] = filepath.Join(testDir, "generated_telemetrytest.go")
+		toGenerate[filepath.Join(tmplDir, "telemetrytest_test.go.tmpl")] = filepath.Join(testDir, "generated_telemetrytest_test.go")
 	}
 
 	if len(md.Metrics) != 0 || len(md.Telemetry.Metrics) != 0 || len(md.ResourceAttributes) != 0 { // if there's metrics or internal metrics, generate documentation for them

cmd/mdatagen/internal/embedded_templates_test.go

@@ -36,6 +36,8 @@ func TestEnsureTemplatesLoaded(t *testing.T) {
 			path.Join(rootDir, "telemetry.go.tmpl"):                {},
 			path.Join(rootDir, "telemetry_test.go.tmpl"):           {},
 			path.Join(rootDir, "testdata", "config.yaml.tmpl"):     {},
+			path.Join(rootDir, "telemetrytest.go.tmpl"):            {},
+			path.Join(rootDir, "telemetrytest_test.go.tmpl"):       {},
 		}
 		count = 0
 	)

cmd/mdatagen/internal/samplereceiver/generated_component_telemetry_test.go

@@ -9,8 +9,10 @@ import (
 
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/otel/sdk/metric/metricdata"
+	"go.opentelemetry.io/otel/sdk/metric/metricdata/metricdatatest"
 
 	"go.opentelemetry.io/collector/cmd/mdatagen/internal/samplereceiver/internal/metadata"
+	"go.opentelemetry.io/collector/cmd/mdatagen/internal/samplereceiver/internal/metadatatest"
 	"go.opentelemetry.io/collector/component/componenttest"
 	"go.opentelemetry.io/collector/consumer/consumertest"
 	"go.opentelemetry.io/collector/receiver/receivertest"
@@ -24,11 +26,11 @@ func TestGeneratedMetrics(t *testing.T) {
 }
 
 func TestComponentTelemetry(t *testing.T) {
-	tt := setupTestTelemetry()
+	tt := metadatatest.SetupTelemetry()
 	factory := NewFactory()
 	receiver, err := factory.CreateMetrics(context.Background(), tt.NewSettings(), componenttest.NewNopHost(), new(consumertest.MetricsSink))
 	require.NoError(t, err)
-	tt.assertMetrics(t, []metricdata.Metrics{
+	tt.AssertMetrics(t, []metricdata.Metrics{
 		{
 			Name:        "otelcol_batch_size_trigger_send",
 			Description: "Number of times the batch was sent due to a size trigger [deprecated since v0.110.0]",
@@ -57,11 +59,11 @@ func TestComponentTelemetry(t *testing.T) {
 				},
 			},
 		},
-	})
+	}, metricdatatest.IgnoreTimestamp())
 	rcv, ok := receiver.(nopReceiver)
 	require.True(t, ok)
 	rcv.initOptionalMetric()
-	tt.assertMetrics(t, []metricdata.Metrics{
+	tt.AssertMetrics(t, []metricdata.Metrics{
 		{
 			Name:        "otelcol_batch_size_trigger_send",
 			Description: "Number of times the batch was sent due to a size trigger [deprecated since v0.110.0]",
@@ -102,6 +104,6 @@ func TestComponentTelemetry(t *testing.T) {
 				},
 			},
 		},
-	})
+	}, metricdatatest.IgnoreTimestamp())
 	require.NoError(t, tt.Shutdown(context.Background()))
 }

cmd/mdatagen/internal/samplereceiver/internal/metadata/generated_telemetry.go

@@ -23,6 +23,7 @@ import (
 	{{- end }}
 )
 
+// Deprecated: [v0.117.0] use metadatatest.Telemetry
 type componentTestTelemetry struct {
 	reader        *sdkmetric.ManualReader
 	meterProvider *sdkmetric.MeterProvider
@@ -44,6 +45,7 @@ func (tt *componentTestTelemetry) newTelemetrySettings() component.TelemetrySett
 	return set
 }
 
+// Deprecated: [v0.116.0] use metadatatest.SetupTelemetry
 func setupTestTelemetry() componentTestTelemetry {
 	reader := sdkmetric.NewManualReader()
 	return componentTestTelemetry{

cmd/mdatagen/internal/samplereceiver/internal/metadatatest/generated_telemetrytest.go

@@ -14,6 +14,9 @@ import (
     {{- end }}
 
 	"go.opentelemetry.io/otel/metric"
+	{{- if .Telemetry.Metrics }}
+	noopmetric "go.opentelemetry.io/otel/metric/noop"
+	{{- end }}
 	"go.opentelemetry.io/otel/trace"
 
 	"go.opentelemetry.io/collector/component"
@@ -128,7 +131,7 @@ func getLeveledMeter(meter metric.Meter, cfgLevel, srvLevel configtelemetry.Leve
 	if cfgLevel <= srvLevel {
 		return meter
 	}
-	return noop.Meter{}
+	return noopmetric.Meter{}
 }
 
 {{- end }}

cmd/mdatagen/internal/samplereceiver/internal/metadatatest/generated_telemetrytest_test.go

@@ -15,7 +15,6 @@ import (
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/component/componenttest"
-	"go.opentelemetry.io/collector/config/configtelemetry"
 )
 
 type mockMeter struct {