What is this?

api/resmap/factory_test.go

@@ -10,10 +10,11 @@ import (
 	"github.com/stretchr/testify/assert"
 	"sigs.k8s.io/kustomize/api/filesys"
 	"sigs.k8s.io/kustomize/api/ifc"
+	"sigs.k8s.io/kustomize/api/konfig"
 	"sigs.k8s.io/kustomize/api/kv"
 	"sigs.k8s.io/kustomize/api/loader"
-	"sigs.k8s.io/kustomize/api/resid"
 	. "sigs.k8s.io/kustomize/api/resmap"
+	"sigs.k8s.io/kustomize/api/resource"
 	resmaptest_test "sigs.k8s.io/kustomize/api/testutils/resmaptest"
 	valtest_test "sigs.k8s.io/kustomize/api/testutils/valtest"
 	"sigs.k8s.io/kustomize/api/types"
@@ -110,8 +111,6 @@ metadata:
 	assert.Equal(t, expYaml, mYaml)
 }
 
-var cmap = resid.Gvk{Version: "v1", Kind: "ConfigMap"}
-
 func TestNewFromConfigMaps(t *testing.T) {
 	type testCase struct {
 		description string
@@ -329,3 +328,69 @@ rules:
 		t.Fatalf("error: %s", err)
 	}
 }
+
+func TestMerge_Empty(t *testing.T) {
+	rm, err := rmF.Merge([]*resource.Resource{})
+	assert.NoError(t, err)
+	assert.Equal(t, 0, rm.Size())
+}
+
+func TestMerge(t *testing.T) {
+	var (
+		err    error
+		yml    []byte
+		r1, r2 *resource.Resource
+	)
+	r1, err = rf.FromBytes([]byte(`apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: my-foo
+spec:
+  bar:
+    B:
+    C: Z
+`))
+	assert.NoError(t, err)
+
+	r2, err = rf.FromBytes([]byte(`apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: my-foo
+spec:
+  bar:
+    C: Z
+    D: W
+  baz:
+    hello: world
+`))
+	assert.NoError(t, err)
+
+	rm, err := rmF.Merge([]*resource.Resource{r1, r2})
+	assert.NoError(t, err)
+
+	yml, err = rm.AsYaml()
+	assert.NoError(t, err)
+
+	assert.Equal(t, konfig.IfApiMachineryElseKyaml(`apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: my-foo
+spec:
+  bar:
+    B: null
+    C: Z
+    D: W
+  baz:
+    hello: world
+`, `apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: my-foo
+spec:
+  bar:
+    C: Z
+    D: W
+  baz:
+    hello: world
+`), string(yml))
+}