Fix subPath tests for Windows

Windows test for subPath is failing due to an issue related to
removeUnusedContainers calls. After image is changed to Agnhost, it
automatically has a args by default. However, there are places to use
container commands instead of args and causing issues.

This is the first step to fix this issue. Next plan to replace
busybox used in Linux with Agnhost which can work for both linux and
windows.

I also mark two subPath tests as LinuxOnly. I think they are not ready
for windows yet. Before they were passing due to wrong reason. The tests
checks failed container status but the contain fails due to other
reasons than what we expected.

Author: jingxu97

test/e2e/storage/testsuites/subpath.go

@@ -234,7 +234,7 @@ func (s *subPathTestSuite) DefineTests(driver TestDriver, pattern testpatterns.T
 		TestBasicSubpath(f, f.Namespace.Name, l.pod)
 	})
 
-	ginkgo.It("should fail if subpath directory is outside the volume [Slow]", func() {
+	ginkgo.It("should fail if subpath directory is outside the volume [Slow][LinuxOnly]", func() {
 		init()
 		defer cleanup()
 
@@ -272,7 +272,7 @@ func (s *subPathTestSuite) DefineTests(driver TestDriver, pattern testpatterns.T
 		testPodFailSubpath(f, l.pod, false)
 	})
 
-	ginkgo.It("should fail if subpath with backstepping is outside the volume [Slow]", func() {
+	ginkgo.It("should fail if subpath with backstepping is outside the volume [Slow][LinuxOnly]", func() {
 		init()
 		defer cleanup()
 
@@ -443,6 +443,7 @@ func (s *subPathTestSuite) DefineTests(driver TestDriver, pattern testpatterns.T
 		// Change volume container to busybox so we can exec later
 		l.pod.Spec.Containers[1].Image = e2evolume.GetTestImage(imageutils.GetE2EImage(imageutils.BusyBox))
 		l.pod.Spec.Containers[1].Command = e2evolume.GenerateScriptCmd("sleep 100000")
+		l.pod.Spec.Containers[1].Args = nil
 
 		ginkgo.By(fmt.Sprintf("Creating pod %s", l.pod.Name))
 		removeUnusedContainers(l.pod)
@@ -618,8 +619,9 @@ func SubpathTestPod(f *framework.Framework, subpath, volumeType string, source *
 }
 
 func containerIsUnused(container *v1.Container) bool {
-	// mountImage with nil Args or with just "mounttest" as Args does nothing. Leave everything else
-	return container.Image == mountImage && (container.Args == nil || (len(container.Args) == 1 && container.Args[0] == "mounttest"))
+	// mountImage with nil command and nil Args or with just "mounttest" as Args does nothing. Leave everything else
+	return container.Image == mountImage && container.Command == nil &&
+		(container.Args == nil || (len(container.Args) == 1 && container.Args[0] == "mounttest"))
 }
 
 // removeUnusedContainers removes containers from a SubpathTestPod that aren't
@@ -830,9 +832,10 @@ func testPodContainerRestartWithHooks(f *framework.Framework, pod *v1.Pod, hooks
 
 	pod.Spec.Containers[0].Image = e2evolume.GetTestImage(imageutils.GetE2EImage(imageutils.BusyBox))
 	pod.Spec.Containers[0].Command = e2evolume.GenerateScriptCmd("sleep 100000")
+	pod.Spec.Containers[0].Args = nil
 	pod.Spec.Containers[1].Image = e2evolume.GetTestImage(imageutils.GetE2EImage(imageutils.BusyBox))
 	pod.Spec.Containers[1].Command = e2evolume.GenerateScriptCmd("sleep 100000")
-
+	pod.Spec.Containers[1].Args = nil
 	hooks.AddLivenessProbe(pod, probeFilePath)
 
 	// Start pod
@@ -1003,9 +1006,10 @@ func testSubpathReconstruction(f *framework.Framework, hostExec utils.HostExec,
 	// Change to busybox
 	pod.Spec.Containers[0].Image = e2evolume.GetTestImage(imageutils.GetE2EImage(imageutils.BusyBox))
 	pod.Spec.Containers[0].Command = e2evolume.GenerateScriptCmd("sleep 100000")
+	pod.Spec.Containers[0].Args = nil
 	pod.Spec.Containers[1].Image = e2evolume.GetTestImage(imageutils.GetE2EImage(imageutils.BusyBox))
 	pod.Spec.Containers[1].Command = e2evolume.GenerateScriptCmd("sleep 100000")
-
+	pod.Spec.Containers[1].Args = nil
 	// If grace period is too short, then there is not enough time for the volume
 	// manager to cleanup the volumes
 	gracePeriod := int64(30)