Add metadata getters and setters to RNode.

These setters completely remove the field if the argument
is empty, rather than setting the field to an empty value,
mimicing apimachinery behavior.

kyaml/yaml/rnode_test.go

@@ -751,3 +751,104 @@ func TestRNodeIsNilOrEmpty(t *testing.T) {
 		t.Fatalf("non-empty list should not be empty")
 	}
 }
+
+const deploymentJSON = `
+{
+  "apiVersion": "apps/v1",
+  "kind": "Deployment",
+  "metadata": {
+    "name": "homer",
+    "namespace": "simpsons",
+    "labels": {
+      "fruit": "apple",
+      "veggie": "carrot"
+    },
+    "annotations": {
+      "area": "51",
+      "greeting": "Take me to your leader."
+    }
+  }
+}
+`
+
+func getNamespaceOrDie(t *testing.T, n *RNode) string {
+	m, err := n.GetNamespace()
+	assert.NoError(t, err)
+	return m
+}
+
+func TestRNodeSetNamespace(t *testing.T) {
+	n := NewRNode(nil)
+	assert.Equal(t, "", getNamespaceOrDie(t, n))
+	assert.NoError(t, n.SetNamespace(""))
+	assert.Equal(t, "", getNamespaceOrDie(t, n))
+	if err := n.UnmarshalJSON([]byte(deploymentJSON)); err != nil {
+		t.Fatalf("unexpected unmarshaljson err: %v", err)
+	}
+	assert.NoError(t, n.SetNamespace("flanders"))
+	assert.Equal(t, "flanders", getNamespaceOrDie(t, n))
+}
+
+func getLabelsOrDie(t *testing.T, n *RNode) map[string]string {
+	m, err := n.GetLabels()
+	assert.NoError(t, err)
+	return m
+}
+
+func TestRNodeSetLabels(t *testing.T) {
+	n := NewRNode(nil)
+	assert.Equal(t, 0, len(getLabelsOrDie(t, n)))
+	assert.NoError(t, n.SetLabels(map[string]string{}))
+	assert.Equal(t, 0, len(getLabelsOrDie(t, n)))
+
+	n = NewRNode(nil)
+	if err := n.UnmarshalJSON([]byte(deploymentJSON)); err != nil {
+		t.Fatalf("unexpected unmarshaljson err: %v", err)
+	}
+	labels := getLabelsOrDie(t, n)
+	assert.Equal(t, 2, len(labels))
+	assert.Equal(t, "apple", labels["fruit"])
+	assert.Equal(t, "carrot", labels["veggie"])
+	assert.NoError(t, n.SetLabels(map[string]string{
+		"label1": "foo",
+		"label2": "bar",
+	}))
+	labels = getLabelsOrDie(t, n)
+	assert.Equal(t, 2, len(labels))
+	assert.Equal(t, "foo", labels["label1"])
+	assert.Equal(t, "bar", labels["label2"])
+	assert.NoError(t, n.SetLabels(map[string]string{}))
+	assert.Equal(t, 0, len(getLabelsOrDie(t, n)))
+}
+
+func getAnnotationsOrDie(t *testing.T, n *RNode) map[string]string {
+	m, err := n.GetAnnotations()
+	assert.NoError(t, err)
+	return m
+}
+
+func TestRNodeGetAnnotations(t *testing.T) {
+	n := NewRNode(nil)
+	assert.Equal(t, 0, len(getAnnotationsOrDie(t, n)))
+	assert.NoError(t, n.SetAnnotations(map[string]string{}))
+	assert.Equal(t, 0, len(getAnnotationsOrDie(t, n)))
+
+	n = NewRNode(nil)
+	if err := n.UnmarshalJSON([]byte(deploymentJSON)); err != nil {
+		t.Fatalf("unexpected unmarshaljson err: %v", err)
+	}
+	annotations := getAnnotationsOrDie(t, n)
+	assert.Equal(t, 2, len(annotations))
+	assert.Equal(t, "51", annotations["area"])
+	assert.Equal(t, "Take me to your leader.", annotations["greeting"])
+	assert.NoError(t, n.SetAnnotations(map[string]string{
+		"annotation1": "foo",
+		"annotation2": "bar",
+	}))
+	annotations = getAnnotationsOrDie(t, n)
+	assert.Equal(t, 2, len(annotations))
+	assert.Equal(t, "foo", annotations["annotation1"])
+	assert.Equal(t, "bar", annotations["annotation2"])
+	assert.NoError(t, n.SetAnnotations(map[string]string{}))
+	assert.Equal(t, 0, len(getAnnotationsOrDie(t, n)))
+}