diff --git a/kyaml/yaml/kfns_test.go b/kyaml/yaml/kfns_test.go
new file mode 100644
index 000000000..7b0e0cb8f
--- /dev/null
+++ b/kyaml/yaml/kfns_test.go
@@ -0,0 +1,60 @@
+package yaml
+
+import (
+	"testing"
+)
+
+var input = `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: the-map
+data:
+  altGreeting: "Good Morning!"
+  enableRisky: "false"
+`
+
+func TestSetLabel(t *testing.T) {
+	rn := MustParse(input)
+	_, err := rn.Pipe(SetLabel("foo", "bar"))
+	if err != nil {
+		t.Fatalf("unexpected error %v", err)
+	}
+	output := rn.MustString()
+
+	expected := `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: the-map
+  labels:
+    foo: 'bar'
+data:
+  altGreeting: "Good Morning!"
+  enableRisky: "false"
+`
+	if output != expected {
+		t.Fatalf("expected \n%s\nbut got \n%s\n", expected, output)
+	}
+}
+
+func TestAnnotation(t *testing.T) {
+	rn := MustParse(input)
+	_, err := rn.Pipe(SetAnnotation("foo", "bar"))
+	if err != nil {
+		t.Fatalf("unexpected error %v", err)
+	}
+	output := rn.MustString()
+
+	expected := `apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: the-map
+  annotations:
+    foo: 'bar'
+data:
+  altGreeting: "Good Morning!"
+  enableRisky: "false"
+`
+	if output != expected {
+		t.Fatalf("expected \n%s\nbut got \n%s\n", expected, output)
+	}
+}