Deduplicate RC/RS controller code.

The code was already 99% similar between RC and RS.
This is a wild idea to try to deduplicate the two controllers
in a type-safe manner without adding tons of boilerplate,
and without using code generation.

They are still separate resources. This is a refactor that isn't
intended to change any behavior.

pkg/controller/replication/replication_controller_utils_test.go

@@ -0,0 +1,184 @@
+/*
+Copyright 2017 The Kubernetes 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 replication
+
+import (
+	"reflect"
+	"testing"
+
+	"k8s.io/api/core/v1"
+)
+
+var (
+	imagePullBackOff v1.ReplicationControllerConditionType = "ImagePullBackOff"
+
+	condImagePullBackOff = func() v1.ReplicationControllerCondition {
+		return v1.ReplicationControllerCondition{
+			Type:   imagePullBackOff,
+			Status: v1.ConditionTrue,
+			Reason: "NonExistentImage",
+		}
+	}
+
+	condReplicaFailure = func() v1.ReplicationControllerCondition {
+		return v1.ReplicationControllerCondition{
+			Type:   v1.ReplicationControllerReplicaFailure,
+			Status: v1.ConditionTrue,
+			Reason: "OtherFailure",
+		}
+	}
+
+	condReplicaFailure2 = func() v1.ReplicationControllerCondition {
+		return v1.ReplicationControllerCondition{
+			Type:   v1.ReplicationControllerReplicaFailure,
+			Status: v1.ConditionTrue,
+			Reason: "AnotherFailure",
+		}
+	}
+
+	status = func() *v1.ReplicationControllerStatus {
+		return &v1.ReplicationControllerStatus{
+			Conditions: []v1.ReplicationControllerCondition{condReplicaFailure()},
+		}
+	}
+)
+
+func TestGetCondition(t *testing.T) {
+	exampleStatus := status()
+
+	tests := []struct {
+		name string
+
+		status     v1.ReplicationControllerStatus
+		condType   v1.ReplicationControllerConditionType
+		condStatus v1.ConditionStatus
+		condReason string
+
+		expected bool
+	}{
+		{
+			name: "condition exists",
+
+			status:   *exampleStatus,
+			condType: v1.ReplicationControllerReplicaFailure,
+
+			expected: true,
+		},
+		{
+			name: "condition does not exist",
+
+			status:   *exampleStatus,
+			condType: imagePullBackOff,
+
+			expected: false,
+		},
+	}
+
+	for _, test := range tests {
+		cond := GetCondition(test.status, test.condType)
+		exists := cond != nil
+		if exists != test.expected {
+			t.Errorf("%s: expected condition to exist: %t, got: %t", test.name, test.expected, exists)
+		}
+	}
+}
+
+func TestSetCondition(t *testing.T) {
+	tests := []struct {
+		name string
+
+		status *v1.ReplicationControllerStatus
+		cond   v1.ReplicationControllerCondition
+
+		expectedStatus *v1.ReplicationControllerStatus
+	}{
+		{
+			name: "set for the first time",
+
+			status: &v1.ReplicationControllerStatus{},
+			cond:   condReplicaFailure(),
+
+			expectedStatus: &v1.ReplicationControllerStatus{Conditions: []v1.ReplicationControllerCondition{condReplicaFailure()}},
+		},
+		{
+			name: "simple set",
+
+			status: &v1.ReplicationControllerStatus{Conditions: []v1.ReplicationControllerCondition{condImagePullBackOff()}},
+			cond:   condReplicaFailure(),
+
+			expectedStatus: &v1.ReplicationControllerStatus{Conditions: []v1.ReplicationControllerCondition{condImagePullBackOff(), condReplicaFailure()}},
+		},
+		{
+			name: "overwrite",
+
+			status: &v1.ReplicationControllerStatus{Conditions: []v1.ReplicationControllerCondition{condReplicaFailure()}},
+			cond:   condReplicaFailure2(),
+
+			expectedStatus: &v1.ReplicationControllerStatus{Conditions: []v1.ReplicationControllerCondition{condReplicaFailure2()}},
+		},
+	}
+
+	for _, test := range tests {
+		SetCondition(test.status, test.cond)
+		if !reflect.DeepEqual(test.status, test.expectedStatus) {
+			t.Errorf("%s: expected status: %v, got: %v", test.name, test.expectedStatus, test.status)
+		}
+	}
+}
+
+func TestRemoveCondition(t *testing.T) {
+	tests := []struct {
+		name string
+
+		status   *v1.ReplicationControllerStatus
+		condType v1.ReplicationControllerConditionType
+
+		expectedStatus *v1.ReplicationControllerStatus
+	}{
+		{
+			name: "remove from empty status",
+
+			status:   &v1.ReplicationControllerStatus{},
+			condType: v1.ReplicationControllerReplicaFailure,
+
+			expectedStatus: &v1.ReplicationControllerStatus{},
+		},
+		{
+			name: "simple remove",
+
+			status:   &v1.ReplicationControllerStatus{Conditions: []v1.ReplicationControllerCondition{condReplicaFailure()}},
+			condType: v1.ReplicationControllerReplicaFailure,
+
+			expectedStatus: &v1.ReplicationControllerStatus{},
+		},
+		{
+			name: "doesn't remove anything",
+
+			status:   status(),
+			condType: imagePullBackOff,
+
+			expectedStatus: status(),
+		},
+	}
+
+	for _, test := range tests {
+		RemoveCondition(test.status, test.condType)
+		if !reflect.DeepEqual(test.status, test.expectedStatus) {
+			t.Errorf("%s: expected status: %v, got: %v", test.name, test.expectedStatus, test.status)
+		}
+	}
+}