watcher/mock: MockHandler

a mock event handler that can be primed with a series of expected
messages.

Useful for testing watcher

watcher/mock/mock.go

@@ -0,0 +1,34 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+package mock
+
+import (
+	"fmt"
+	"testing"
+
+	n "git.st8l.com/luxolus/kdnotify/schema/notify"
+)
+
+type MockHandler struct {
+	T           *testing.T
+	Expected    []n.VrrpMessage
+	HandlerFunc func(t *testing.T, expected, actual *n.VrrpMessage) bool
+}
+
+func (m *MockHandler) ProcessVrrp(actual n.VrrpMessage) error {
+	var expected *n.VrrpMessage
+	if len(m.Expected) > 1 {
+		expected = &m.Expected[0]
+		m.Expected = m.Expected[1:]
+	}
+
+	if !m.HandlerFunc(m.T, expected, &actual) {
+		return fmt.Errorf("MockHandler.HandlerFunc test fail")
+	}
+
+	return nil
+}