gen-test: don't expose diff + attributions

internal/code-generator/generator/generator_test.go

@@ -10,7 +10,6 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/go-enry/go-enry/v2/internal/code-generator/generator/diff"
 	"github.com/go-enry/go-enry/v2/internal/tokenizer"
 
 	"github.com/stretchr/testify/assert"
@@ -327,7 +326,7 @@ func (s *GeneratorTestSuite) TestGenerationFiles() {
 		// assert.Equal(s.T(), expected, actual, "Test %s", test.name)
 		if expected != actual {
 			assert.Fail(s.T(), fmt.Sprintf("%s output is different from %q", test.name, test.wantOut))
-			diff, err := diff.Diff(gold, out)
+			diff, err := text_diff(gold, out)
 			if err != nil {
 				s.T().Logf("Failed produce a diff between expected and actual: %s", err.Error())
 				s.T().Logf("Expected %q", expected[:400])

internal/code-generator/generator/generator_test_util.go

@@ -1,4 +1,9 @@
-package diff
+// Copyright 2017 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+// https://cs.opensource.google/go/x/perf/+/e8d778a6:LICENSE
+
+package generator
 
 import (
 	"bytes"
@@ -7,25 +12,11 @@ import (
 	"os/exec"
 )
 
-func writeTempFile(dir, prefix string, data []byte) (string, error) {
+// text_diff returns a human-readable description of the differences between s1 and s2.
-	file, err := os.CreateTemp(dir, prefix)
+// It essentially is https://cs.opensource.google/go/x/perf/+/e8d778a6:internal/diff/diff.go
-	if err != nil {
+// Used only in code generator tests, as a debugging aid.
-		return "", err
+// It is not part of any release artifact and is not distibuted with enry.
-	}
+func text_diff(b1, b2 []byte) (string, error) {
-
-	_, err = file.Write(data)
-	if err1 := file.Close(); err == nil {
-		err = err1
-	}
-	if err != nil {
-		os.Remove(file.Name())
-		return "", err
-	}
-	return file.Name(), nil
-}
-
-// Diff returns a human-readable description of the differences between s1 and s2.
-func Diff(b1, b2 []byte) (string, error) {
 	if bytes.Equal(b1, b2) {
 		return "", nil
 	}
@@ -56,3 +47,20 @@ func Diff(b1, b2 []byte) (string, error) {
 	}
 	return string(data), nil
 }
+
+func writeTempFile(dir, prefix string, data []byte) (string, error) {
+	file, err := os.CreateTemp(dir, prefix)
+	if err != nil {
+		return "", err
+	}
+
+	_, err = file.Write(data)
+	if err1 := file.Close(); err == nil {
+		err = err1
+	}
+	if err != nil {
+		os.Remove(file.Name())
+		return "", err
+	}
+	return file.Name(), nil
+}