Expose some internal types/funcs in envtest

This exposes a few pieces of the new APIs in internal/testing as public
in envtest.  These types are effectively part of public APIs (they're
referenced by public methods or fields of APIServer, ControlPlane, etc),
so we should let users name them.

Author: DirectXMan12

pkg/envtest/server.go

@@ -59,20 +59,48 @@ const (
 	defaultKubebuilderControlPlaneStopTimeout  = 20 * time.Second
 )
 
-// ControlPlane is the re-exported ControlPlane type from the internal testing package
-type ControlPlane = controlplane.ControlPlane
+// internal types we expose as part of our public API
+type (
+	// ControlPlane is the re-exported ControlPlane type from the internal testing package
+	ControlPlane = controlplane.ControlPlane
 
-// APIServer is the re-exported APIServer type from the internal testing package
-type APIServer = controlplane.APIServer
+	// APIServer is the re-exported APIServer from the internal testing package
+	APIServer = controlplane.APIServer
 
-// Etcd is the re-exported Etcd type from the internal testing package
-type Etcd = controlplane.Etcd
+	// Etcd is the re-exported Etcd from the internal testing package
+	Etcd = controlplane.Etcd
 
-// User represents a Kubernetes user to provision for auth purposes.
-type User = controlplane.User
+	// User represents a Kubernetes user to provision for auth purposes.
+	User = controlplane.User
 
-// AuthenticatedUser represets a Kubernetes user that's been provisioned.
-type AuthenticatedUser = controlplane.AuthenticatedUser
+	// AuthenticatedUser represets a Kubernetes user that's been provisioned.
+	AuthenticatedUser = controlplane.AuthenticatedUser
+
+	// ListenAddr indicates the address and port that the API server should listen on.
+	ListenAddr = process.ListenAddr
+
+	// SecureServing contains details describing how the API server should serve
+	// its secure endpoint.
+	SecureServing = controlplane.SecureServing
+
+	// Authn is an authentication method that can be used with the control plane to
+	// provision users.
+	Authn = controlplane.Authn
+
+	// Arguments allows configuring a process's flags.
+	Arguments = process.Arguments
+
+	// Arg is a single flag with one or more values.
+	Arg = process.Arg
+)
+
+var (
+	// EmptyArguments constructs a new set of flags with nothing set.
+	//
+	// This is mostly useful for testing helper methods -- you'll want to call
+	// Configure on the APIServer (or etcd) to configure their arguments.
+	EmptyArguments = process.EmptyArguments
+)
 
 // Environment creates a Kubernetes test environment that will start / stop the Kubernetes control plane and
 // install extension APIs

pkg/internal/testing/controlplane/apiserver.go

@@ -15,8 +15,6 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/internal/testing/process"
 )
 
-// TODO: listenaddr needs to be exposes publically so we can set insecureserving
-
 const (
 	// saKeyFile is the name of the service account signing private key file
 	saKeyFile = "sa-signer.key"