Use Ginkgo Skip() to avoid failing when tests are skipped

- Added util methods: Skipf, SkipUnlessNodeCountIsAtLeast, SkipIfProviderIs,
  and SkipUnlessProviderIs

test/e2e/reboot.go

@@ -50,6 +50,12 @@ var _ = Describe("Reboot", func() {
 		var err error
 		c, err = loadClient()
 		Expect(err).NotTo(HaveOccurred())
+
+		// These tests requires SSH, so the provider check should be identical to there
+		// (the limiting factor is the implementation of util.go's getSigner(...)).
+
+		// Cluster must support node reboot
+		SkipUnlessProviderIs("gce", "aws")
 	})
 
 	It("each node by ordering clean reboot and ensure they function upon restart", func() {
@@ -90,15 +96,6 @@ var _ = Describe("Reboot", func() {
 })
 
 func testReboot(c *client.Client, rebootCmd string) {
-	// This test requires SSH, so the provider check should be identical to
-	// there (the limiting factor is the implementation of util.go's
-	// getSigner(...)).
-	provider := testContext.Provider
-	if !providerIs("aws", "gce") {
-		By(fmt.Sprintf("Skipping reboot test, which is not implemented for %s", provider))
-		return
-	}
-
 	// Get all nodes, and kick off the test on each.
 	nodelist, err := listNodes(c, labels.Everything(), fields.Everything())
 	if err != nil {
@@ -106,7 +103,7 @@ func testReboot(c *client.Client, rebootCmd string) {
 	}
 	result := make(chan bool, len(nodelist.Items))
 	for _, n := range nodelist.Items {
-		go rebootNode(c, provider, n.ObjectMeta.Name, rebootCmd, result)
+		go rebootNode(c, testContext.Provider, n.ObjectMeta.Name, rebootCmd, result)
 	}
 
 	// Wait for all to finish and check the final result.