[#143] Fix transformToS3Error function

Unwrap error before checking for s3 error

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

api/handler/util_test.go

@@ -0,0 +1,64 @@
+package handler
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+
+	s3errors "git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/errors"
+	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/layer"
+	"github.com/stretchr/testify/require"
+)
+
+func TestTransformS3Errors(t *testing.T) {
+	for _, tc := range []struct {
+		name     string
+		err      error
+		expected s3errors.ErrorCode
+	}{
+		{
+			name:     "simple std error to internal error",
+			err:      errors.New("some error"),
+			expected: s3errors.ErrInternalError,
+		},
+		{
+			name:     "layer access denied error to s3 access denied error",
+			err:      layer.ErrAccessDenied,
+			expected: s3errors.ErrAccessDenied,
+		},
+		{
+			name:     "wrapped layer access denied error to s3 access denied error",
+			err:      fmt.Errorf("wrap: %w", layer.ErrAccessDenied),
+			expected: s3errors.ErrAccessDenied,
+		},
+		{
+			name:     "layer node access denied error to s3 access denied error",
+			err:      layer.ErrNodeAccessDenied,
+			expected: s3errors.ErrAccessDenied,
+		},
+		{
+			name:     "layer gateway timeout error to s3 gateway timeout error",
+			err:      layer.ErrGatewayTimeout,
+			expected: s3errors.ErrGatewayTimeout,
+		},
+		{
+			name:     "s3 error to s3 error",
+			err:      s3errors.GetAPIError(s3errors.ErrInvalidPart),
+			expected: s3errors.ErrInvalidPart,
+		},
+		{
+			name:     "wrapped s3 error to s3 error",
+			err:      fmt.Errorf("wrap: %w", s3errors.GetAPIError(s3errors.ErrInvalidPart)),
+			expected: s3errors.ErrInvalidPart,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			err := transformToS3Error(tc.err)
+			s3err, ok := err.(s3errors.Error)
+			require.True(t, ok, "error must be s3 error")
+			require.Equalf(t, tc.expected, s3err.ErrCode,
+				"expected: '%s', got: '%s'",
+				s3errors.GetAPIError(tc.expected).Code, s3errors.GetAPIError(s3err.ErrCode).Code)
+		})
+	}
+}