tests: Add framework to mock virtcontainers

Add a simple test framework to allow the behaviour of the virtcontainers
package to be mocked.

This change introduces a RVC interface and provides two implementations:
one for virtcontainers itself (rvc-implementation.go) and another mock
implementation for the tests to allow the behaviour of the
virtcontainers package to be modified (rvc-implementation_test.go). By
only accessing the virtcontainers implementation via the "vci" variable,
the tests can be switched to the mock implementation.

Note that this mocking is used rather than testing virtcontainers
directly since the virtcontainers API is already tested in that package:
the mock framework thus avoids duplication of test code and allows more
fine-grained error scenarios to be handled.

This change also introduces a single new test, TestCreate(), that
increases the unit test coverage of create.go by using the new framework
to force create() to fail due to a virtcontainers failure in
CreatePod().

Fixes clearcontainers#401.

Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>

create.go

@@ -183,7 +183,7 @@ func createPod(ociSpec oci.CompatOCISpec, runtimeConfig oci.RuntimeConfig,
 		return vc.Process{}, err
 	}
 
-	pod, err := vc.CreatePod(podConfig)
+	pod, err := vci.CreatePod(podConfig)
 	if err != nil {
 		return vc.Process{}, err
 	}
@@ -209,7 +209,7 @@ func createContainer(ociSpec oci.CompatOCISpec, containerID, bundlePath,
 		return vc.Process{}, err
 	}
 
-	_, c, err := vc.CreateContainer(podID, contConfig)
+	_, c, err := vci.CreateContainer(podID, contConfig)
 	if err != nil {
 		return vc.Process{}, err
 	}

create_test.go

@@ -20,6 +20,8 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 var testPID = 100
@@ -95,3 +97,42 @@ func TestCreatePIDFileEmptyPathSuccessful(t *testing.T) {
 		t.Fatalf("This test should not fail (pidFilePath %q, pid %d)", file, testPID)
 	}
 }
+
+func TestCreate(t *testing.T) {
+	// change behaviour
+	testingImpl.listPodFunc = listPodNoPods
+	testingImpl.forceFailure = true
+
+	defer func() {
+		// reset
+		testingImpl.listPodFunc = nil
+		testingImpl.forceFailure = false
+	}()
+
+	tmpdir, err := ioutil.TempDir("", "")
+	if err != nil {
+		panic(err)
+	}
+
+	defer os.RemoveAll(tmpdir)
+
+	containerID := "foo"
+	bundlePath := filepath.Join(tmpdir, "bundle")
+
+	err = os.MkdirAll(bundlePath, testDirMode)
+	assert.NoError(t, err)
+
+	err = makeOCIBundle(bundlePath)
+	assert.NoError(t, err)
+
+	console := "/dev/pts/999"
+	pidFilePath := filepath.Join(tmpdir, "pidfile.txt")
+	detach := false
+	runtimeConfig, err := newRuntimeConfig(tmpdir, console)
+	assert.NoError(t, err)
+
+	err = create(containerID, bundlePath, console, pidFilePath, detach, runtimeConfig)
+
+	assert.Error(t, err)
+	assert.True(t, isMockError(err))
+}

delete.go

@@ -114,11 +114,11 @@ func delete(containerID string, force bool) error {
 }
 
 func deletePod(podID string) error {
-	if _, err := vc.StopPod(podID); err != nil {
+	if _, err := vci.StopPod(podID); err != nil {
 		return err
 	}
 
-	if _, err := vc.DeletePod(podID); err != nil {
+	if _, err := vci.DeletePod(podID); err != nil {
 		return err
 	}
 
@@ -127,12 +127,12 @@ func deletePod(podID string) error {
 
 func deleteContainer(podID, containerID string, forceStop bool) error {
 	if forceStop {
-		if _, err := vc.StopContainer(podID, containerID); err != nil {
+		if _, err := vci.StopContainer(podID, containerID); err != nil {
 			return err
 		}
 	}
 
-	if _, err := vc.DeleteContainer(podID, containerID); err != nil {
+	if _, err := vci.DeleteContainer(podID, containerID); err != nil {
 		return err
 	}
 

exec.go

@@ -230,7 +230,7 @@ func execute(context *cli.Context) error {
 		Detach:      noNeedForOutput(params.detach, params.ociProcess.Terminal),
 	}
 
-	_, _, process, err := vc.EnterContainer(podID, params.cID, cmd)
+	_, _, process, err := vci.EnterContainer(podID, params.cID, cmd)
 	if err != nil {
 		return err
 	}

kill.go

@@ -116,7 +116,7 @@ func kill(containerID, signal string, all bool) error {
 		return fmt.Errorf("Container %s not ready or running, cannot send a signal", containerID)
 	}
 
-	if err := vc.KillContainer(podID, containerID, signum, all); err != nil {
+	if err := vci.KillContainer(podID, containerID, signum, all); err != nil {
 		return err
 	}
 

list.go

@@ -26,7 +26,6 @@ import (
 
 	"github.com/urfave/cli"
 
-	vc "github.com/containers/virtcontainers"
 	oci "github.com/containers/virtcontainers/pkg/oci"
 )
 
@@ -200,7 +199,7 @@ func getContainers(context *cli.Context) ([]fullContainerState, error) {
 		return nil, err
 	}
 
-	podList, err := vc.ListPod()
+	podList, err := vci.ListPod()
 	if err != nil {
 		return nil, err
 	}

main.go

@@ -22,7 +22,7 @@ import (
 	"strings"
 
 	"github.com/Sirupsen/logrus"
-	vc "github.com/containers/virtcontainers"
+	"github.com/clearcontainers/runtime/pkg/rvc"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/urfave/cli"
 )
@@ -50,6 +50,14 @@ NOTES:
 
 var ccLog = logrus.New()
 
+// concrete virtcontainer implementation
+var virtcontainersImpl = &vcImpl{}
+
+// vci is used to access a particular virtcontainers implementation.
+// Normally, it refers to the official package, but is re-assigned in
+// the tests to allow virtcontainers to be mocked.
+var vci rvc.RVC = virtcontainersImpl
+
 func beforeSubcommands(context *cli.Context) error {
 	if userWantsUsage(context) || (context.NArg() == 1 && (context.Args()[0] == "cc-check")) {
 		// No setup required if the user just
@@ -80,7 +88,7 @@ func beforeSubcommands(context *cli.Context) error {
 	}
 
 	// Set virtcontainers logger.
-	vc.SetLogger(ccLog)
+	vci.SetLogger(ccLog)
 
 	ignoreLogging := false
 	if context.NArg() == 1 && context.Args()[0] == "cc-env" {