image-tests: allow disabling of local booting

On some environments (like RHEL gating) there's no virtualization available.
This commit adds -disable-local-boot argument to osbuild-image-tests. When
this argument is present, the local booting is skipped. This doesn't affect
the cloud booting, the test binary still tries to do that. If no credentials
are available, the fall back to local booting will be skipped if
-disable-local-boot is given.

cmd/osbuild-image-tests/main_test.go

@@ -40,6 +40,8 @@ type testcaseStruct struct {
 	}
 }
 
+var disableLocalBoot = flag.Bool("disable-local-boot", false, "when this flag is given, no images are booted locally using qemu (this does not affect testing in clouds)")
+
 // mutex to enforce only one osbuild instance run at a time, see below
 var osbuildMutex sync.Mutex
 
@@ -178,6 +180,9 @@ func testSSH(t *testing.T, address string, privateKey string, ns *netNS) {
 }
 
 func testBootUsingQemu(t *testing.T, imagePath string) {
+	if *disableLocalBoot {
+		t.Skip("local booting was disabled by -disable-local-boot, skipping")
+	}
 	err := withNetworkNamespace(func(ns netNS) error {
 		return withBootedQemuImage(imagePath, ns, func() error {
 			testSSH(t, "localhost", constants.TestPaths.PrivateKey, &ns)