allow to provide fake vm implementation

Introduce a new constructor method `newClientWithVirtualMachine` in machine
client that would have an additional VirtualMachine argument, this would be
kept package private so that it's used only by tests in the same package.

Author: cfergeau

pkg/crc/machine/client.go

@@ -30,21 +30,30 @@ type Client interface {
 }
 
 type client struct {
-	name   string
-	debug  bool
-	config crcConfig.Storage
+	name           string
+	debug          bool
+	config         crcConfig.Storage
+	virtualMachine VirtualMachine
 
 	diskDetails *memoize.Memoizer
 	ramDetails  *memoize.Memoizer
 }
 
 func NewClient(name string, debug bool, config crcConfig.Storage) Client {
+	return newClientWithVirtualMachine(name, debug, config, nil)
+}
+
+// newClientWithVirtualMachine creates a Client instance with an overridden VirtualMachine implementation.
+// It would not create a new VirtualMachine object. This method is primarily created for usage in tests so
+// that we can pass a fake VirtualMachine implementation.
+func newClientWithVirtualMachine(name string, debug bool, config crcConfig.Storage, vm VirtualMachine) Client {
 	return &client{
-		name:        name,
-		debug:       debug,
-		config:      config,
-		diskDetails: memoize.NewMemoizer(time.Minute, 5*time.Minute),
-		ramDetails:  memoize.NewMemoizer(30*time.Second, 2*time.Minute),
+		name:           name,
+		debug:          debug,
+		config:         config,
+		diskDetails:    memoize.NewMemoizer(time.Minute, 5*time.Minute),
+		ramDetails:     memoize.NewMemoizer(30*time.Second, 2*time.Minute),
+		virtualMachine: vm,
 	}
 }
 

pkg/crc/machine/start.go

@@ -625,7 +625,7 @@ func (client *client) Start(ctx context.Context, startConfig types.StartConfig)
 }
 
 func (client *client) IsRunning() (bool, error) {
-	vm, err := loadVirtualMachine(client.name, client.useVSock())
+	vm, err := loadVirtualMachineLazily(client.virtualMachine, client.name, client.useVSock())
 	if err != nil {
 		return false, errors.Wrap(err, "Cannot load machine")
 	}

pkg/crc/machine/stop.go

@@ -20,7 +20,7 @@ func (client *client) Stop() (state.State, error) {
 	if running, _ := client.IsRunning(); !running {
 		return state.Error, errors.New("Instance is already stopped")
 	}
-	vm, err := loadVirtualMachine(client.name, client.useVSock())
+	vm, err := loadVirtualMachineLazily(client.virtualMachine, client.name, client.useVSock())
 	if err != nil {
 		return state.Error, errors.Wrap(err, "Cannot load machine")
 	}

pkg/crc/machine/virtualmachine.go

@@ -50,6 +50,13 @@ func (err *MissingHostError) Error() string {
 
 var errInvalidBundleMetadata = errors.New("Error loading bundle metadata")
 
+func loadVirtualMachineLazily(vm VirtualMachine, name string, useVSock bool) (VirtualMachine, error) {
+	if vm != nil {
+		return vm, nil
+	}
+	return loadVirtualMachine(name, useVSock)
+}
+
 func loadVirtualMachine(name string, useVSock bool) (VirtualMachine, error) {
 	apiClient := libmachine.NewClient(constants.MachineBaseDir)
 	exists, err := apiClient.Exists(name)