Add unit tests for CheckPushPermissions

pkg/executor/push.go

@@ -99,6 +99,13 @@ var defaultX509Handler systemCertLoader = func() CertPool {
 	}
 }
 
+// for testing
+var (
+	fs                        = afero.NewOsFs()
+	execCommand               = exec.Command
+	checkRemotePushPermission = remote.CheckPushPermission
+)
+
 // CheckPushPermissions checks that the configured credentials can be used to
 // push to every specified destination.
 func CheckPushPermissions(opts *config.KanikoOptions) error {
@@ -122,9 +129,8 @@ func CheckPushPermissions(opts *config.KanikoOptions) error {
 		if strings.Contains(destRef.RegistryStr(), "gcr.io") {
 			// Checking for existence of docker.config as it's normally required for
 			// authenticated registries and prevent overwriting user provided docker conf
-			if _, err := os.Stat("/kaniko/.docker/config.json"); os.IsNotExist(err) {
-				cmd := exec.Command("docker-credential-gcr", "configure-docker")
-				if err := cmd.Run(); err != nil {
+			if _, err := fs.Stat("/kaniko/.docker/config.json"); os.IsNotExist(err) {
+				if err := execCommand("docker-credential-gcr", "configure-docker").Run(); err != nil {
 					return errors.Wrap(err, "error while configuring docker-credential-gcr helper")
 				}
 			}
@@ -138,7 +144,7 @@ func CheckPushPermissions(opts *config.KanikoOptions) error {
 			destRef.Repository.Registry = newReg
 		}
 		tr := makeTransport(opts, registryName, defaultX509Handler)
-		if err := remote.CheckPushPermission(destRef, creds.GetKeychain(), tr); err != nil {
+		if err := checkRemotePushPermission(destRef, creds.GetKeychain(), tr); err != nil {
 			return errors.Wrapf(err, "checking push permission for %q", destRef)
 		}
 		checked[destRef.Context().RepositoryStr()] = true
@@ -245,8 +251,6 @@ func DoPush(image v1.Image, opts *config.KanikoOptions) error {
 	return writeImageOutputs(image, destRefs)
 }
 
-var fs = afero.NewOsFs()
-
 func writeImageOutputs(image v1.Image, destRefs []name.Tag) error {
 	dir := os.Getenv("BUILDER_OUTPUT")
 	if dir == "" {

pkg/executor/push_test.go

@@ -24,11 +24,13 @@ import (
 	"io/ioutil"
 	"net/http"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"testing"
 
 	"github.com/GoogleContainerTools/kaniko/pkg/config"
 	"github.com/GoogleContainerTools/kaniko/testutil"
+	"github.com/google/go-containerregistry/pkg/authn"
 	"github.com/google/go-containerregistry/pkg/name"
 	"github.com/google/go-containerregistry/pkg/v1/layout"
 	"github.com/google/go-containerregistry/pkg/v1/random"
@@ -307,3 +309,73 @@ func Test_makeTransport(t *testing.T) {
 		})
 	}
 }
+
+var called = false
+
+func fakeExecCommand(command string, args ...string) *exec.Cmd {
+	called = true
+	cs := []string{"-test.run=TestHelperProcess", "--", command}
+	cs = append(cs, args...)
+	cmd := exec.Command(os.Args[0], cs...)
+	cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
+	return cmd
+}
+
+func fakeCheckPushPermission(ref name.Reference, kc authn.Keychain, t http.RoundTripper) error {
+	return nil
+}
+
+func TestCheckPushPermissionsGCR(t *testing.T) {
+	execCommand = fakeExecCommand
+	checkRemotePushPermission = fakeCheckPushPermission
+	defer func() { called = false }()
+
+	opts := config.KanikoOptions{
+		Destinations: []string{"gcr.io/test-image"},
+	}
+	fs = afero.NewMemMapFs()
+	//afero.WriteFile(fs, "/kaniko/.docker/config.json", []byte(""), os.FileMode(0644))
+	CheckPushPermissions(&opts)
+	if called != true {
+		t.Error("execCommand should have been called")
+	}
+}
+
+func TestCheckPushPermissionsGCRExistingDockerConf(t *testing.T) {
+	execCommand = fakeExecCommand
+	checkRemotePushPermission = fakeCheckPushPermission
+	defer func() { called = false }()
+
+	opts := config.KanikoOptions{
+		Destinations: []string{"gcr.io/test-image"},
+	}
+	fs = afero.NewMemMapFs()
+	afero.WriteFile(fs, "/kaniko/.docker/config.json", []byte(""), os.FileMode(0644))
+	CheckPushPermissions(&opts)
+	if called != false {
+		t.Error("execCommand should not have been called")
+	}
+}
+
+func TestCheckPushPermissionsLocalRegistry(t *testing.T) {
+	execCommand = fakeExecCommand
+	checkRemotePushPermission = fakeCheckPushPermission
+	defer func() { called = false }()
+
+	opts := config.KanikoOptions{
+		Destinations: []string{"localhost:5000/test-image"},
+	}
+	fs = afero.NewMemMapFs()
+	CheckPushPermissions(&opts)
+	if called != false {
+		t.Error("execCommand should not have been called")
+	}
+}
+
+func TestHelperProcess(t *testing.T) {
+	if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" {
+		return
+	}
+	fmt.Fprintf(os.Stdout, "fake result")
+	os.Exit(0)
+}