Implement render method for container exec

Currently it returns NotImplemented error, and that's not
correct behavior. Since this kind of executor has the bundle
inside, it should be properly rendered.

Change-Id: I4c4e417b064236130b4349560fa3eb2615a0f824
Signed-off-by: Ruslan Aliev <raliev@mirantis.com>

pkg/phase/executors/container.go

@@ -173,8 +173,12 @@ func (c *ContainerExecutor) Validate() error {
 }
 
 // Render executor documents
-func (c *ContainerExecutor) Render(_ io.Writer, _ ifc.RenderOptions) error {
-	return commonerrors.ErrNotImplemented{}
+func (c *ContainerExecutor) Render(w io.Writer, o ifc.RenderOptions) error {
+	bundle, err := c.ExecutorBundle.SelectBundle(o.FilterSelector)
+	if err != nil {
+		return err
+	}
+	return bundle.Write(w)
 }
 
 func (c *ContainerExecutor) setConfig() error {

pkg/phase/executors/container_test.go

@@ -13,6 +13,7 @@
 package executors_test
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"testing"
@@ -273,6 +274,56 @@ func TestSetKubeConfig(t *testing.T) {
 	}
 }
 
+func TestContainerRender(t *testing.T) {
+	testCases := []struct {
+		name        string
+		bundleData  []byte
+		opts        ifc.RenderOptions
+		expectedErr error
+		expectedOut string
+	}{
+		{
+			name:        "empty bundle",
+			bundleData:  []byte{},
+			opts:        ifc.RenderOptions{},
+			expectedOut: "",
+			expectedErr: nil,
+		},
+		{
+			name: "valid bundle",
+			bundleData: []byte(`apiVersion: unittest.org/v1alpha1
+kind: Test
+metadata:
+  name: TestName`),
+			opts: ifc.RenderOptions{FilterSelector: document.NewSelector().ByKind("Test").ByName("TestName")},
+			expectedOut: `---
+apiVersion: unittest.org/v1alpha1
+kind: Test
+metadata:
+  name: TestName
+...
+`,
+			expectedErr: nil,
+		},
+	}
+
+	buf := &bytes.Buffer{}
+	for _, tc := range testCases {
+		tt := tc
+		t.Run(tt.name, func(t *testing.T) {
+			bundle, err := document.NewBundleFromBytes(tt.bundleData)
+			require.NoError(t, err)
+			e := executors.ContainerExecutor{
+				ExecutorBundle: bundle,
+			}
+			err = e.Render(buf, tt.opts)
+			assert.Equal(t, tt.expectedErr, err)
+			assert.Equal(t, tt.expectedOut, buf.String())
+			buf.Reset()
+		})
+	}
+}
+
 type fakeKubeConfig struct {
 	getFile func() (string, kubeconfig.Cleanup, error)
 }