fix(test): added coverage of serialisation

lib/LoggingEvent.js

@@ -30,11 +30,10 @@ class LoggingEvent {
   }
 
   serialise() {
-    // JSON.stringify(new Error('test')) returns {}, which is not really useful for us.
-    // The following allows us to serialize errors correctly.
-    // Validate that we really are in this case
     try {
       const logData = this.data.map((e) => {
+        // JSON.stringify(new Error('test')) returns {}, which is not really useful for us.
+        // The following allows us to serialize errors correctly.
         if (e && e.stack && CircularJSON.stringify(e) === '{}') {
           e = { message: e.message, stack: e.stack };
         }
@@ -54,10 +53,8 @@ class LoggingEvent {
   static deserialise(serialised) {
     let event;
     try {
-      event = CircularJSON.parse(serialised);
-      event.startTime = new Date(event.startTime);
-      event.level = levels.getLevel(event.level.levelStr);
-      event.data = event.data.map((e) => {
+      const rehydratedEvent = CircularJSON.parse(serialised);
+      rehydratedEvent.data = rehydratedEvent.data.map((e) => {
         if (e && e.stack) {
           const fakeError = new Error(e.message);
           fakeError.stack = e.stack;
@@ -65,6 +62,15 @@ class LoggingEvent {
         }
         return e;
       });
+      event = new LoggingEvent(
+        rehydratedEvent.categoryName,
+        levels.getLevel(rehydratedEvent.level.levelStr),
+        rehydratedEvent.data,
+        rehydratedEvent.context
+      );
+      event.startTime = new Date(rehydratedEvent.startTime);
+      event.pid = rehydratedEvent.pid;
+      event.cluster = rehydratedEvent.cluster;
     } catch (e) {
       event = new LoggingEvent(
         'log4js',

test/tap/LoggingEvent-test.js

@@ -0,0 +1,42 @@
+const test = require('tap').test;
+const LoggingEvent = require('../../lib/LoggingEvent');
+const levels = require('../../lib/levels');
+
+test('LoggingEvent', (batch) => {
+  batch.test('should serialise to JSON', (t) => {
+    const event = new LoggingEvent('cheese', levels.DEBUG, ['log message'], { user: 'bob' });
+    // set the event date to a known value
+    event.startTime = new Date(Date.UTC(2018, 1, 4, 18, 30, 23, 10));
+    const rehydratedEvent = JSON.parse(event.serialise());
+    t.equal(rehydratedEvent.startTime, '2018-02-04T18:30:23.010Z');
+    t.equal(rehydratedEvent.categoryName, 'cheese');
+    t.equal(rehydratedEvent.level.levelStr, 'DEBUG');
+    t.equal(rehydratedEvent.data.length, 1);
+    t.equal(rehydratedEvent.data[0], 'log message');
+    t.equal(rehydratedEvent.context.user, 'bob');
+    t.end();
+  });
+
+  batch.test('should deserialise from JSON', (t) => {
+    const dehydratedEvent = `{
+      "startTime": "2018-02-04T10:25:23.010Z",
+      "categoryName": "biscuits",
+      "level": {
+        "levelStr": "INFO"
+      },
+      "data": [ "some log message", { "x": 1 } ],
+      "context": { "thing": "otherThing" }
+    }`;
+    const event = LoggingEvent.deserialise(dehydratedEvent);
+    t.type(event, LoggingEvent);
+    t.same(event.startTime, new Date(Date.UTC(2018, 1, 4, 10, 25, 23, 10)));
+    t.equal(event.categoryName, 'biscuits');
+    t.same(event.level, levels.INFO);
+    t.equal(event.data[0], 'some log message');
+    t.equal(event.data[1].x, 1);
+    t.equal(event.context.thing, 'otherThing');
+    t.end();
+  });
+
+  batch.end();
+});