Improve coverage of mdatagen (#11352)

Bump coverage of _cmd/mdatagen/internal/command.go_ from
[70.40%](https://app.codecov.io/gh/open-telemetry/opentelemetry-collector/commit/b1f38a2960608b1b95e0f13547f0bddeebed1175?dropdown=coverage&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry)
to
[79.37%](https://app.codecov.io/gh/open-telemetry/opentelemetry-collector/commit/9ff6b2b9ce557f5b3cd3dce4d1e48bd16a56f86d?dropdown=coverage&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry)

Fixes
#11219

---------

Co-authored-by: Alex Boten <223565+codeboten@users.noreply.github.com>

cmd/mdatagen/internal/command.go

@@ -361,6 +361,16 @@ func templatize(tmplFile string, md Metadata) *template.Template {
 			}).ParseFS(TemplateFS, strings.ReplaceAll(tmplFile, "\\", "/")))
 }
 
+func executeTemplate(tmplFile string, md Metadata, goPackage string) ([]byte, error) {
+	tmpl := templatize(tmplFile, md)
+	buf := bytes.Buffer{}
+
+	if err := tmpl.Execute(&buf, TemplateContext{Metadata: md, Package: goPackage}); err != nil {
+		return []byte{}, fmt.Errorf("failed executing template: %w", err)
+	}
+	return buf.Bytes(), nil
+}
+
 func inlineReplace(tmplFile string, outputFile string, md Metadata, start string, end string) error {
 	var readmeContents []byte
 	var err error
@@ -373,20 +383,16 @@ func inlineReplace(tmplFile string, outputFile string, md Metadata, start string
 		return nil
 	}
 
-	tmpl := templatize(tmplFile, md)
-	buf := bytes.Buffer{}
-
 	if md.GithubProject == "" {
 		md.GithubProject = "open-telemetry/opentelemetry-collector-contrib"
 	}
 
-	if err := tmpl.Execute(&buf, TemplateContext{Metadata: md, Package: "metadata"}); err != nil {
-		return fmt.Errorf("failed executing template: %w", err)
+	buf, err := executeTemplate(tmplFile, md, "metadata")
+	if err != nil {
+		return err
 	}
 
-	result := buf.String()
-
-	s := re.ReplaceAllString(string(readmeContents), result)
+	s := re.ReplaceAllString(string(readmeContents), string(buf))
 	if err := os.WriteFile(outputFile, []byte(s), 0600); err != nil {
 		return fmt.Errorf("failed writing %q: %w", outputFile, err)
 	}
@@ -395,21 +401,17 @@ func inlineReplace(tmplFile string, outputFile string, md Metadata, start string
 }
 
 func generateFile(tmplFile string, outputFile string, md Metadata, goPackage string) error {
-	tmpl := templatize(tmplFile, md)
-	buf := bytes.Buffer{}
-
-	if err := tmpl.Execute(&buf, TemplateContext{Metadata: md, Package: goPackage}); err != nil {
-		return fmt.Errorf("failed executing template: %w", err)
-	}
-
 	if err := os.Remove(outputFile); err != nil && !errors.Is(err, os.ErrNotExist) {
 		return fmt.Errorf("unable to remove generated file %q: %w", outputFile, err)
 	}
 
-	result := buf.Bytes()
+	result, err := executeTemplate(tmplFile, md, goPackage)
+	if err != nil {
+		return err
+	}
 	var formatErr error
 	if strings.HasSuffix(outputFile, ".go") {
-		if formatted, err := format.Source(buf.Bytes()); err == nil {
+		if formatted, err := format.Source(result); err == nil {
 			result = formatted
 		} else {
 			formatErr = fmt.Errorf("failed formatting %s:%w", outputFile, err)

cmd/mdatagen/internal/command_test.go

@@ -12,11 +12,23 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"go.opentelemetry.io/collector/component"
 )
 
+func TestNewCommand(t *testing.T) {
+	cmd, err := NewCommand()
+	require.NoError(t, err)
+
+	assert.NotNil(t, cmd)
+	assert.IsType(t, &cobra.Command{}, cmd)
+	assert.Equal(t, "mdatagen", cmd.Use)
+	assert.True(t, cmd.SilenceUsage)
+}
+
 func TestRunContents(t *testing.T) {
 	tests := []struct {
 		yml                             string
@@ -36,6 +48,16 @@ func TestRunContents(t *testing.T) {
 			yml:     "invalid.yaml",
 			wantErr: true,
 		},
+		{
+			yml:                 "basic_connector.yaml",
+			wantErr:             false,
+			wantStatusGenerated: true,
+		},
+		{
+			yml:                 "basic_receiver.yaml",
+			wantErr:             false,
+			wantStatusGenerated: true,
+		},
 		{
 			yml:                  "metrics_and_type.yaml",
 			wantMetricsGenerated: true,
@@ -344,7 +366,7 @@ Some info about a component
 			componentClass: "receiver",
 			distros:        []string{"contrib"},
 			codeowners: &Codeowners{
-				Active: []string{"foo"},
+				Active: []string{"open-telemetry/collector-approvers"},
 			},
 		},
 		{

cmd/mdatagen/internal/testdata/basic_connector.yaml

@@ -0,0 +1,6 @@
+type: test
+
+status:
+  class: connector
+  stability:
+    beta: [traces_to_traces]

cmd/mdatagen/internal/testdata/basic_receiver.yaml

@@ -0,0 +1,6 @@
+type: test
+
+status:
+  class: receiver
+  stability:
+    beta: [logs]

cmd/mdatagen/internal/testdata/readme_with_status_codeowners.md

@@ -6,7 +6,7 @@
 | Stability     | [beta]: metrics   |
 | Distributions | [contrib] |
 | Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Areceiver%2Ffoo%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Areceiver%2Ffoo) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Areceiver%2Ffoo%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Areceiver%2Ffoo) |
-| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@foo](https://www.github.com/foo) |
+| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@open-telemetry/collector-approvers](https://github.com/orgs/open-telemetry/teams/collector-approvers) |
 
 [beta]: https://github.com/open-telemetry/opentelemetry-collector#beta
 [contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib