[VOL-2235] Mocks and interfaces for rw-core

This update consists of mocks that are used by the rw-core
during unit testing.  It also includes interfaces used for unit
tests.

Change-Id: I20ca1455c358113c3aa897acc6355e0ddbc614b7
diff --git a/rw_core/mocks/common_test.go b/rw_core/mocks/common_test.go
new file mode 100644
index 0000000..1ff5700
--- /dev/null
+++ b/rw_core/mocks/common_test.go
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2019-present Open Networking Foundation
+ *
+ * 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 mocks
+
+import (
+	"github.com/opencord/voltha-lib-go/v2/pkg/log"
+)
+
+const (
+	logLevel = log.FatalLevel
+)
+
+// Unit test initialization. This init() function handles all unit tests in
+// the current directory.
+func init() {
+	// Setup this package so that it's log level can be modified at run time
+	_, err := log.AddPackage(log.JSON, logLevel, log.Fields{"instanceId": "mocks"})
+	if err != nil {
+		panic(err)
+	}
+}