feat: add -build-tag flag.

README.md

@@ -44,6 +44,8 @@ moq [flags] source-dir interface [interface2 [interface3 [...]]]
     	show the version for moq
   -with-resets
     	generate functions to facilitate resetting calls made to a mock
+  -build-tag
+    	specify and optional go:build tag for the generated files, e.g. `-build-tag test`.
 
 Specifying an alias for the mock is also supported with the format 'interface:alias'
 

internal/template/template_data.go

@@ -17,6 +17,7 @@ type Data struct {
 	StubImpl        bool
 	SkipEnsure      bool
 	WithResets      bool
+	BuildTag        string
 }
 
 // MocksSomeMethod returns true of any one of the Mocks has at least 1

main.go

@@ -20,6 +20,7 @@ type userFlags struct {
 	outFile    string
 	pkgName    string
 	formatter  string
+	buildTag   string
 	stubImpl   bool
 	skipEnsure bool
 	withResets bool
@@ -40,6 +41,7 @@ func main() {
 	flag.BoolVar(&flags.remove, "rm", false, "first remove output file, if it exists")
 	flag.BoolVar(&flags.withResets, "with-resets", false,
 		"generate functions to facilitate resetting calls made to a mock")
+	flag.StringVar(&flags.buildTag, "build-tag", "", "go:build tag to inject into the mock, e.g. `test`")
 
 	flag.Usage = func() {
 		fmt.Println(`moq [flags] source-dir interface [interface2 [interface3 [...]]]`)
@@ -90,6 +92,7 @@ func run(flags userFlags) error {
 		StubImpl:   flags.stubImpl,
 		SkipEnsure: flags.skipEnsure,
 		WithResets: flags.withResets,
+		BuildTag:   flags.buildTag,
 	})
 	if err != nil {
 		return err

pkg/moq/moq.go

@@ -29,6 +29,7 @@ type Config struct {
 	StubImpl   bool
 	SkipEnsure bool
 	WithResets bool
+	BuildTag   string
 }
 
 // New makes a new Mocker for the specified package directory.
@@ -83,6 +84,7 @@ func (m *Mocker) Mock(w io.Writer, namePairs ...string) error {
 		StubImpl:   m.cfg.StubImpl,
 		SkipEnsure: m.cfg.SkipEnsure,
 		WithResets: m.cfg.WithResets,
+		BuildTag:   m.cfg.BuildTag,
 	}
 
 	if data.MocksSomeMethod() {

pkg/moq/moq_test.go

@@ -615,6 +615,22 @@ func TestEmptyInterface(t *testing.T) {
 	}
 }
 
+func TestEmptyInterfaceWithBuildTag(t *testing.T) {
+	m, err := New(Config{SrcDir: "testpackages/emptyinterface", BuildTag: "test"})
+	if err != nil {
+		t.Fatalf("moq.New: %s", err)
+	}
+	var buf bytes.Buffer
+	err = m.Mock(&buf, "Empty")
+	if err != nil {
+		t.Errorf("mock error: %s", err)
+	}
+	s := buf.String()
+	if !strings.HasPrefix(s, "//go:build test\n\n") {
+		t.Error("missing `//go:build test` prefix on:", s)
+	}
+}
+
 func TestGoGenerateVendoredPackages(t *testing.T) {
 	cmd := exec.Command("go", "generate", "./...")
 	cmd.Dir = "testpackages/gogenvendoring"