🧑‍💻 Created GoldenEqual testutil

internal/testutil/golden_equal.go

@@ -0,0 +1,69 @@
+package testutil
+
+import (
+	"errors"
+	"flag"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+var update *bool = flag.Bool("update", false, "save current tests results as golden files")
+
+// GoldenEqual compares the bytes of the provided r with the contents of the
+// golden file for a complete data match.
+//
+// When running tests with the -update flag, the contents of golden-files will
+// be overwritten with the provided contents of r, creating the testdata/
+// directory if it does not exist.
+//
+//nolint:gocognit,gocyclo
+func GoldenEqual(tb testing.TB, r io.Reader) {
+	tb.Helper()
+
+	wd, err := os.Getwd()
+	if err != nil {
+		tb.Fatal("cannot get current working directory path:", err)
+	}
+
+	actual, err := io.ReadAll(r)
+	if err != nil {
+		tb.Fatal("cannot read provided data:", err)
+	}
+
+	dir := filepath.Join(wd, "testdata")
+	file := filepath.Join(dir, tb.Name()[4:]+".golden")
+
+	if *update {
+		_, err = os.Stat(dir)
+		if err != nil && !errors.Is(err, os.ErrExist) && !errors.Is(err, os.ErrNotExist) {
+			tb.Fatal("cannot create testdata folder for golden files:", err)
+		}
+
+		if errors.Is(err, os.ErrNotExist) {
+			if err = os.Mkdir(dir, os.ModePerm); err != nil {
+				tb.Fatal("cannot create testdata folder for golden files:", err)
+			}
+		}
+
+		if err = os.WriteFile(file, actual, os.ModePerm); err != nil {
+			tb.Fatal("cannot write data into golden file:", err)
+		}
+
+		tb.Skip("skipped due force updating golden file")
+
+		return
+	}
+
+	expected, err := os.ReadFile(file)
+	if err != nil {
+		tb.Fatal("cannot read golden file data:", err)
+	}
+
+	if diff := cmp.Diff(string(actual), string(expected)); diff != "" {
+		tb.Error(diff)
+	}
+}