add ability to update yaml path while preserving comments

pkg/utils/yaml_utils/yaml_utils_test.go

@@ -0,0 +1,64 @@
+package yaml_utils
+
+import "testing"
+
+func TestUpdateYaml(t *testing.T) {
+	tests := []struct {
+		name        string
+		in          string
+		path        []string
+		value       string
+		expectedOut string
+		expectedErr string
+	}{
+		{
+			name:        "update value",
+			in:          "foo: bar\n",
+			path:        []string{"foo"},
+			value:       "baz",
+			expectedOut: "foo: baz\n",
+			expectedErr: "",
+		},
+		{
+			name:        "add new key and value",
+			in:          "foo: bar\n",
+			path:        []string{"foo2"},
+			value:       "baz",
+			expectedOut: "foo: bar\nfoo2: baz\n",
+			expectedErr: "",
+		},
+		{
+			name:        "preserve inline comment",
+			in:          "foo: bar # my comment\n",
+			path:        []string{"foo2"},
+			value:       "baz",
+			expectedOut: "foo: bar # my comment\nfoo2: baz\n",
+			expectedErr: "",
+		},
+		{
+			name:  "nested update",
+			in:    "foo:\n  bar: baz\n",
+			path:  []string{"foo", "bar"},
+			value: "qux",
+			// indentation is not preserved. See https://github.com/go-yaml/yaml/issues/899
+			expectedOut: "foo:\n    bar: qux\n",
+			expectedErr: "",
+		},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			out, err := UpdateYaml([]byte(test.in), test.path, test.value)
+			if test.expectedErr != "" {
+				if err == nil {
+					t.Errorf("expected error %q but got none", 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))
+			}
+		})
+	}
+}