Cleanup: improve test setup and check for the right error string

Use the assert package to check expectations; also, check for the exact error
message instead of just whether any error occurred.

pkg/utils/yaml_utils/yaml_utils_test.go

@@ -1,6 +1,10 @@
 package yaml_utils
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
 
 func TestUpdateYaml(t *testing.T) {
 	tests := []struct {
@@ -49,16 +53,14 @@ func TestUpdateYaml(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(test.name, func(t *testing.T) {
-			out, err := UpdateYaml([]byte(test.in), test.path, test.value)
+			out, actualErr := UpdateYaml([]byte(test.in), test.path, test.value)
-			if test.expectedErr != "" {
+			if test.expectedErr == "" {
-				if err == nil {
+				assert.NoError(t, actualErr)
-					t.Errorf("expected error %q but got none", test.expectedErr)
+			} else {
-				}
+				assert.EqualError(t, actualErr, test.expectedErr)
-			} else if err != nil {
-				t.Errorf("unexpected error: %v", err)
-			} else if string(out) != test.expectedOut {
-				t.Errorf("expected %q but got %q", test.expectedOut, string(out))
 			}
+
+			assert.Equal(t, test.expectedOut, string(out))
 		})
 	}
 }