feat: add immediate watcher and test wait ready (#104)

## Description

Adds and immediate watcher for unit testing. This change also expands
the wait for ready test using the immediate watcher.

## Related Issue

N/A

kubernetes/wait.go

@@ -70,3 +70,31 @@ func WaitForReady(ctx context.Context, sw watcher.StatusWatcher, objs []object.O
 	}
 	return nil
 }
+
+// ImmediateWatcher should only be used for testing and returns the set status immediatly.
+type ImmediateWatcher struct {
+	status status.Status
+}
+
+// NewImmediateWatcher returns a ImmediateWatcher.
+func NewImmediateWatcher(status status.Status) *ImmediateWatcher {
+	return &ImmediateWatcher{
+		status: status,
+	}
+}
+
+// Watch watches the given objects and immediatly returns the configured status.
+func (w *ImmediateWatcher) Watch(_ context.Context, objs object.ObjMetadataSet, _ watcher.Options) <-chan event.Event {
+	eventCh := make(chan event.Event, len(objs))
+	for _, obj := range objs {
+		eventCh <- event.Event{
+			Type: event.ResourceUpdateEvent,
+			Resource: &event.ResourceStatus{
+				Identifier: obj,
+				Status:     w.status,
+			},
+		}
+	}
+	close(eventCh)
+	return eventCh
+}

kubernetes/wait_test.go

@@ -9,10 +9,27 @@ import (
 
 	"github.com/stretchr/testify/require"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/cli-utils/pkg/kstatus/status"
 	"sigs.k8s.io/cli-utils/pkg/kstatus/watcher"
 	"sigs.k8s.io/cli-utils/pkg/object"
 )
 
+func TestWaitForReady(t *testing.T) {
+	sw := NewImmediateWatcher(status.CurrentStatus)
+	objs := []object.ObjMetadata{
+		{
+			GroupKind: schema.GroupKind{
+				Group: "apps",
+				Kind:  "Deployment",
+			},
+			Namespace: "foo",
+			Name:      "bar",
+		},
+	}
+	err := WaitForReady(context.Background(), sw, objs)
+	require.NoError(t, err)
+}
+
 func TestWaitForReadyCanceled(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()