[cmd/mdatagen] Move component config test from cmd/builder

The generated tests are skipped in contrib because they cause the CI timeouts. We moved the lifecycle tests to the tests generated by mdatagen, but the config/factory smoke tests are still part of the files generated by cmd/builder.

Recently, loadbalancing exporter got an invalid camelCase config field because of this coverage gap.

This change moves the config/factory tests from cmd/builder to cmd/mdatagen. So they are always generated for every component even if they are not used in any collector bundle.

.chloggen/mdatagen-introduce-config-factory-tests.yaml

@@ -0,0 +1,26 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: cmd/mdatagen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Generate config and factory tests covering their requirements.
+
+# One or more tracking issues or pull requests related to the change
+issues: [9940]
+
+# (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: |
+  The tests are moved from cmd/builder.
+
+# 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: []

cmd/builder/internal/builder/main.go

@@ -80,7 +80,6 @@ func Generate(cfg Config) error {
 		mainOthersTemplate,
 		mainWindowsTemplate,
 		componentsTemplate,
-		componentsTestTemplate,
 		goModTemplate,
 	} {
 		if err := processAndWrite(cfg, tmpl, tmpl.Name(), cfg); err != nil {

cmd/builder/internal/builder/templates.go

@@ -13,10 +13,6 @@ var (
 	componentsBytes    []byte
 	componentsTemplate = parseTemplate("components.go", componentsBytes)
 
-	//go:embed templates/components_test.go.tmpl
-	componentsTestBytes    []byte
-	componentsTestTemplate = parseTemplate("components_test.go", componentsTestBytes)
-
 	//go:embed templates/main.go.tmpl
 	mainBytes    []byte
 	mainTemplate = parseTemplate("main.go", mainBytes)

cmd/mdatagen/main.go

@@ -62,11 +62,9 @@ func run(ymlPath string) error {
 				filepath.Join(codeDir, "generated_status.go"), md, "metadata"); err != nil {
 				return err
 			}
-			if !md.Tests.SkipLifecycle || !md.Tests.SkipShutdown {
-				if err = generateFile(filepath.Join(tmplDir, "component_test.go.tmpl"),
-					filepath.Join(ymlDir, "generated_component_test.go"), md, packageName); err != nil {
-					return err
-				}
+			if err = generateFile(filepath.Join(tmplDir, "component_test.go.tmpl"),
+				filepath.Join(ymlDir, "generated_component_test.go"), md, packageName); err != nil {
+				return err
 			}
 		}
 

cmd/mdatagen/main_test.go

@@ -21,7 +21,6 @@ func TestRunContents(t *testing.T) {
 		wantMetricsGenerated bool
 		wantConfigGenerated  bool
 		wantStatusGenerated  bool
-		wantTestsGenerated   bool
 		wantErr              bool
 	}{
 		{
@@ -45,27 +44,22 @@ func TestRunContents(t *testing.T) {
 		},
 		{
 			yml:                 "with_tests_receiver.yaml",
-			wantTestsGenerated:  true,
 			wantStatusGenerated: true,
 		},
 		{
 			yml:                 "with_tests_exporter.yaml",
-			wantTestsGenerated:  true,
 			wantStatusGenerated: true,
 		},
 		{
 			yml:                 "with_tests_processor.yaml",
-			wantTestsGenerated:  true,
 			wantStatusGenerated: true,
 		},
 		{
 			yml:                 "with_tests_extension.yaml",
-			wantTestsGenerated:  true,
 			wantStatusGenerated: true,
 		},
 		{
 			yml:                 "with_tests_connector.yaml",
-			wantTestsGenerated:  true,
 			wantStatusGenerated: true,
 		},
 	}
@@ -120,14 +114,10 @@ foo
 				require.Contains(t, string(contents), "foo")
 			}
 
-			if tt.wantTestsGenerated {
-				require.FileExists(t, filepath.Join(tmpdir, "generated_component_test.go"))
-				contents, err := os.ReadFile(filepath.Join(tmpdir, "generated_component_test.go")) // nolint: gosec
-				require.NoError(t, err)
-				require.Contains(t, string(contents), "func Test")
-			} else {
-				require.NoFileExists(t, filepath.Join(tmpdir, "generated_component_test.go"))
-			}
+			require.FileExists(t, filepath.Join(tmpdir, "generated_component_test.go"))
+			contents, err := os.ReadFile(filepath.Join(tmpdir, "generated_component_test.go")) // nolint: gosec
+			require.NoError(t, err)
+			require.Contains(t, string(contents), "func Test")
 		})
 	}
 }

cmd/mdatagen/templates/component_test.go.tmpl

@@ -49,6 +49,14 @@ import (
 	{{- end }}
 )
 
+func TestComponentConfigStruct(t *testing.T) {
+	require.NoError(t, componenttest.CheckConfigStruct(NewFactory().CreateDefaultConfig()))
+}
+
+func TestComponentFactoryType(t *testing.T) {
+	require.Equal(t, "{{ .Type }}", NewFactory().Type().String())
+}
+
 {{ if isExporter -}}
 func TestComponentLifecycle(t *testing.T) {
 	factory := NewFactory()