Condition checkable utilities (#364)

* add the new files

* checkpoint

* use duck

* test –> testing

apis/testing/conditions.go

@@ -0,0 +1,61 @@
+/*
+Copyright 2019 The Knative Authors
+ Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package testing
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/knative/pkg/apis"
+	duckv1b1 "github.com/knative/pkg/apis/duck/v1beta1"
+	corev1 "k8s.io/api/core/v1"
+)
+
+// CheckCondition checks if condition `c` on `cc` has value `cs`.
+func CheckCondition(s *duckv1b1.Status, c apis.ConditionType, cs corev1.ConditionStatus) error {
+	cond := s.GetCondition(c)
+	if cond == nil {
+		return fmt.Errorf("condition %v is nil", c)
+	}
+	if cond.Status != cs {
+		return fmt.Errorf("condition(%v) = %v, wanted: %v", c, cond, cs)
+	}
+	return nil
+}
+
+// CheckConditionOngoing checks if the condition is in state `Unknown`.
+func CheckConditionOngoing(s *duckv1b1.Status, c apis.ConditionType, t *testing.T) {
+	t.Helper()
+	if err := CheckCondition(s, c, corev1.ConditionUnknown); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// CheckConditionFailed checks if the condition is in state `False`.
+func CheckConditionFailed(s *duckv1b1.Status, c apis.ConditionType, t *testing.T) {
+	t.Helper()
+	if err := CheckCondition(s, c, corev1.ConditionFalse); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// CheckConditionSucceeded checks if the condition is in state `True`.
+func CheckConditionSucceeded(s *duckv1b1.Status, c apis.ConditionType, t *testing.T) {
+	t.Helper()
+	if err := CheckCondition(s, c, corev1.ConditionTrue); err != nil {
+		t.Fatal(err)
+	}
+}