[ONOS-7683] Add JSON codecs for FlowInfo and StatsInfo with tests

Change-Id: I12560e5f72e704a72a59465de347ddb32051aabb
diff --git a/apps/openstacktelemetry/app/src/test/java/org/onosproject/openstacktelemetry/codec/StatsInfoJsonMatcher.java b/apps/openstacktelemetry/app/src/test/java/org/onosproject/openstacktelemetry/codec/StatsInfoJsonMatcher.java
new file mode 100644
index 0000000..ffebaf5
--- /dev/null
+++ b/apps/openstacktelemetry/app/src/test/java/org/onosproject/openstacktelemetry/codec/StatsInfoJsonMatcher.java
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2018-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 org.onosproject.openstacktelemetry.codec;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import org.hamcrest.Description;
+import org.hamcrest.TypeSafeDiagnosingMatcher;
+import org.onosproject.openstacktelemetry.api.StatsInfo;
+
+/**
+ * Hamcrest matcher for StatsInfoJsonCodec.
+ */
+public final class StatsInfoJsonMatcher extends TypeSafeDiagnosingMatcher<JsonNode> {
+
+    private final StatsInfo statsInfo;
+
+    private static final String STARTUP_TIME = "startupTime";
+    private static final String FST_PKT_ARR_TIME = "fstPktArrTime";
+    private static final String LST_PKT_OFFSET = "lstPktOffset";
+    private static final String PREV_ACC_BYTES = "prevAccBytes";
+    private static final String PREV_ACC_PKTS = "prevAccPkts";
+    private static final String CURR_ACC_BYTES = "currAccBytes";
+    private static final String CURR_ACC_PKTS = "currAccPkts";
+    private static final String ERROR_PKTS = "errorPkts";
+    private static final String DROP_PKTS = "dropPkts";
+
+    private StatsInfoJsonMatcher(StatsInfo statsInfo) {
+        this.statsInfo = statsInfo;
+    }
+
+    @Override
+    protected boolean matchesSafely(JsonNode jsonNode, Description description) {
+
+        // check startup time
+        long jsonStartupTime = jsonNode.get(STARTUP_TIME).asLong();
+        long startupTime = statsInfo.startupTime();
+        if (jsonStartupTime != startupTime) {
+            description.appendText("startup time was " + jsonStartupTime);
+            return false;
+        }
+
+        // check first packet arrival time
+        long jsonFstPktArrTime = jsonNode.get(FST_PKT_ARR_TIME).asLong();
+        long fstPktArrTime = statsInfo.fstPktArrTime();
+        if (jsonFstPktArrTime != fstPktArrTime) {
+            description.appendText("first packet arrival time was " + jsonFstPktArrTime);
+            return false;
+        }
+
+        // check last packet offset
+        int jsonLstPktOffset = jsonNode.get(LST_PKT_OFFSET).asInt();
+        int lstPktOffset = statsInfo.lstPktOffset();
+        if (jsonLstPktOffset != lstPktOffset) {
+            description.appendText("last packet offset was " + jsonLstPktOffset);
+            return false;
+        }
+
+        // check previous accumulated bytes
+        long jsonPrevAccBytes = jsonNode.get(PREV_ACC_BYTES).asLong();
+        long preAccBytes = statsInfo.prevAccBytes();
+        if (jsonPrevAccBytes != preAccBytes) {
+            description.appendText("previous accumulated bytes was " + jsonPrevAccBytes);
+            return false;
+        }
+
+        // check previous accumulated packets
+        int jsonPreAccPkts = jsonNode.get(PREV_ACC_PKTS).asInt();
+        int preAccPkts = statsInfo.prevAccPkts();
+        if (jsonPreAccPkts != preAccPkts) {
+            description.appendText("previous accumulated packets was " + jsonPreAccPkts);
+            return false;
+        }
+
+        // check current accumulated bytes
+        long jsonCurrAccBytes = jsonNode.get(CURR_ACC_BYTES).asLong();
+        long currAccBytes = statsInfo.currAccBytes();
+        if (jsonCurrAccBytes != currAccBytes) {
+            description.appendText("current accumulated bytes was " + jsonCurrAccBytes);
+            return false;
+        }
+
+        // check current accumulated packets
+        int jsonCurrAccPkts = jsonNode.get(CURR_ACC_PKTS).asInt();
+        int currAccPkts = statsInfo.currAccPkts();
+        if (jsonCurrAccPkts != currAccPkts) {
+            description.appendText("current accumulated packets was " + jsonCurrAccPkts);
+            return false;
+        }
+
+        // check error packets
+        short jsonErrorPkts = (short) jsonNode.get(ERROR_PKTS).asInt();
+        short errorPkts = statsInfo.errorPkts();
+        if (jsonErrorPkts != errorPkts) {
+            description.appendText("error packets was " + jsonErrorPkts);
+            return false;
+        }
+
+        // check drop packets
+        short jsonDropPkts = (short) jsonNode.get(DROP_PKTS).asInt();
+        short dropPkts = statsInfo.dropPkts();
+        if (jsonDropPkts != dropPkts) {
+            description.appendText("drop packets was " + jsonDropPkts);
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public void describeTo(Description description) {
+        description.appendText(statsInfo.toString());
+    }
+
+    /**
+     * Factory to allocate a stats info matcher.
+     *
+     * @param statsInfo stats info object we are looking for
+     * @return matcher
+     */
+    public static StatsInfoJsonMatcher matchStatsInfo(StatsInfo statsInfo) {
+        return new StatsInfoJsonMatcher(statsInfo);
+    }
+}