Introduce -reusenamespace test flag (#1383)

* Introduce -reusenamespace test flag

* allows for reusing test namespaces that were created in advance
(possibly by a cluster admininstrator)

* Fix gofmt

lib/test/flags.go

@@ -28,6 +28,7 @@ var Flags = InitializeFlags()
 // ClientFlags define the flags that are needed to run the e2e tests.
 type ClientFlags struct {
 	DockerConfigJSON string
+	ReuseNamespace   bool
 }
 
 // InitializeFlags initializes the client's flags
@@ -37,6 +38,9 @@ func InitializeFlags() *ClientFlags {
 	dockerConfigJSON := os.Getenv("DOCKER_CONFIG_JSON")
 	flag.StringVar(&f.DockerConfigJSON, "dockerconfigjson", dockerConfigJSON,
 		"Provide the path to Docker configuration file in json format. Defaults to $DOCKER_CONFIG_JSON")
+	// Might be useful in restricted environments where namespaces need to be
+	// created by a user with increased privileges (admin).
+	flag.BoolVar(&f.ReuseNamespace, "reusenamespace", false, "Whether to re-use namespace for test if it already exists.")
 
 	return &f
 }

lib/test/integration.go

@@ -44,9 +44,14 @@ type KnTest struct {
 // NewKnTest creates a new KnTest object
 func NewKnTest() (*KnTest, error) {
 	ns := ""
-	// try next 20 namespace before giving up creating a namespace if it already exists
+	// Try next 20 namespace before giving up creating a namespace if it already exists
 	for i := 0; i < 20; i++ {
 		ns = NextNamespace()
+		if Flags.ReuseNamespace {
+			// Re-using existing namespace, no need to create it.
+			// The namespace is supposed to be created in advance.
+			break
+		}
 		err := CreateNamespace(ns)
 		if err == nil {
 			break
@@ -77,6 +82,10 @@ func NewKnTest() (*KnTest, error) {
 
 // Teardown clean up
 func (test *KnTest) Teardown() error {
+	// If we're reusing existing namespaces leave the deletion to the creator.
+	if Flags.ReuseNamespace {
+		return nil
+	}
 	return DeleteNamespace(test.namespace)
 }