[Builder]: Generate test file for config struct check (#4594)

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

cmd/builder/internal/builder/main.go

@@ -60,33 +60,16 @@ func Generate(cfg Config) error {
 		return fmt.Errorf("failed to create output path: %w", err)
 	}
 
-	for _, file := range []struct {
-		outFile string
-		tmpl    *template.Template
-	}{
-		{
-			"main.go",
-			mainTemplate,
-		},
-		{
-			"main_others.go",
-			mainOthersTemplate,
-		},
-		{
-			"main_windows.go",
-			mainWindowsTemplate,
-		},
-		{
-			"components.go",
-			componentsTemplate,
-		},
-		{
-			"go.mod",
-			goModTemplate,
-		},
+	for _, tmpl := range []*template.Template{
+		mainTemplate,
+		mainOthersTemplate,
+		mainWindowsTemplate,
+		componentsTemplate,
+		componentsTestTemplate,
+		goModTemplate,
 	} {
-		if err := processAndWrite(cfg, file.tmpl, file.outFile, cfg); err != nil {
-			return fmt.Errorf("failed to generate source file with destination %q, source: %q: %w", file.outFile, file.tmpl.Name(), err)
+		if err := processAndWrite(cfg, tmpl, tmpl.Name(), cfg); err != nil {
+			return fmt.Errorf("failed to generate source file %q: %w", tmpl.Name(), err)
 		}
 	}
 

cmd/builder/internal/builder/templates.go

@@ -22,23 +22,27 @@ import (
 var (
 	//go:embed templates/components.go.tmpl
 	componentsBytes    []byte
-	componentsTemplate = parseTemplate("component_header.go.tmpl", componentsBytes)
+	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.tmpl", mainBytes)
+	mainTemplate = parseTemplate("main.go", mainBytes)
 
 	//go:embed templates/main_others.go.tmpl
 	mainOthersBytes    []byte
-	mainOthersTemplate = parseTemplate("main_others.go.tmpl", mainOthersBytes)
+	mainOthersTemplate = parseTemplate("main_others.go", mainOthersBytes)
 
 	//go:embed templates/main_windows.go.tmpl
 	mainWindowsBytes    []byte
-	mainWindowsTemplate = parseTemplate("main_windows.go.tmpl", mainWindowsBytes)
+	mainWindowsTemplate = parseTemplate("main_windows.go", mainWindowsBytes)
 
 	//go:embed templates/go.mod.tmpl
 	goModBytes    []byte
-	goModTemplate = parseTemplate("go.mod.tmpl", goModBytes)
+	goModTemplate = parseTemplate("go.mod", goModBytes)
 )
 
 func parseTemplate(name string, bytes []byte) *template.Template {

cmd/builder/internal/builder/templates/components_test.go.tmpl

@@ -0,0 +1,29 @@
+// Code generated by "go.opentelemetry.io/collector/cmd/builder". DO NOT EDIT.
+
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.opentelemetry.io/collector/config/configtest"
+)
+
+func TestValidateConfigs(t *testing.T) {
+	factories, err := components()
+	assert.NoError(t, err)
+
+	for _, factory := range factories.Receivers {
+		assert.NoError(t, configtest.CheckConfigStruct(factory.CreateDefaultConfig()))
+	}
+	for _, factory := range factories.Processors {
+		assert.NoError(t, configtest.CheckConfigStruct(factory.CreateDefaultConfig()))
+	}
+	for _, factory := range factories.Exporters {
+		assert.NoError(t, configtest.CheckConfigStruct(factory.CreateDefaultConfig()))
+	}
+	for _, factory := range factories.Extensions {
+		assert.NoError(t, configtest.CheckConfigStruct(factory.CreateDefaultConfig()))
+	}
+}

cmd/otelcorecol/go.mod

@@ -5,6 +5,7 @@ module go.opentelemetry.io/collector/cmd/otelcorecol
 go 1.17
 
 require (
+	github.com/stretchr/testify v1.7.0
 	go.opentelemetry.io/collector v0.41.0
 	golang.org/x/sys v0.0.0-20211205182925-97ca703d548d
 )
@@ -14,6 +15,7 @@ require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cenkalti/backoff/v4 v4.1.2 // indirect
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/felixge/httpsnoop v1.0.2 // indirect
 	github.com/go-kit/log v0.1.0 // indirect
 	github.com/go-logfmt/logfmt v0.5.0 // indirect
@@ -36,6 +38,7 @@ require (
 	github.com/mitchellh/mapstructure v1.4.3 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	github.com/mostynb/go-grpc-compression v1.1.15 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c // indirect
 	github.com/prometheus/client_golang v1.11.0 // indirect
 	github.com/prometheus/client_model v0.2.0 // indirect
@@ -72,6 +75,7 @@ require (
 	google.golang.org/grpc v1.43.0 // indirect
 	google.golang.org/protobuf v1.27.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )
 
 replace go.opentelemetry.io/collector => ../../