Continuity: fix TTFI when EventTiming plugin is missing

plugins/continuity.js

@@ -3348,7 +3348,7 @@
 		 * Analyzes Interactions
 		 */
 		function analyze(startTime) {
-			var fid;
+			var fid, ttfi, ET;
 
 			impl.addToBeacon("c.i.dc", externalMetrics.interactionDelayed());
 			impl.addToBeacon("c.i.dt", externalMetrics.interactionDelayedTime());
@@ -3357,9 +3357,10 @@
 			// Only send FID and TTFI Timers once
 			if (!sentTimers) {
 				// defer to EventTiming's FID if available
-				if (BOOMR.plugins.EventTiming &&
-				    BOOMR.plugins.EventTiming.is_enabled()) {
-					fid = BOOMR.plugins.EventTiming.metrics.firstInputDelay();
+				ET = BOOMR.plugins.EventTiming;
+				if (ET && ET.is_enabled()) {
+					fid = ET.metrics.firstInputDelay();
+					ttfi = ET.metrics.timeToFirstInteraction();
 				}
 
 				if (!fid && firstInputDelay !== null) {
@@ -3369,7 +3370,7 @@
 				if (fid) {
 					impl.addToBeacon("c.fid", Math.ceil(fid), true);
 
-					impl.addToBeacon("c.ttfi", BOOMR.plugins.EventTiming.metrics.timeToFirstInteraction() ||
+					impl.addToBeacon("c.ttfi", ttfi ||
 					    externalMetrics.timeToFirstInteraction());
 
 					sentTimers = true;

tests/page-templates/21-continuity/45-interaction-no-eventtiming.html

@@ -0,0 +1,43 @@
+<%= header %>
+<!--
+Same as 13-interaction but without the EventTiming plugin
+-->
+<%= boomerangScript %>
+<p>45-interaction-no-eventtiming loading...</p>
+<script src="45-interaction-no-eventtiming.js" type="text/javascript"></script>
+<script>
+// test that `c.ttfi` can be set without the EventTiming plugin
+delete BOOMR.plugins.EventTiming;
+
+BOOMR_test.init({
+	testAfterOnBeacon: true,
+	Continuity: {
+		enabled: true
+	}
+});
+
+try {
+	// the event timestamp is set when the object is created
+	var ev = document.createEvent("Event");
+	ev.initEvent("keydown", true, true);
+	ev.keyCode = 27;
+}
+catch (e) {
+	window.cannotCreateMouseEvent = true;
+}
+
+// click
+window.ttfi = BOOMR.now();
+
+// dispatch event is synchronous. Wait 20ms between the event creation and dispatch
+BOOMR_test.busy(20);
+document.dispatchEvent(ev);
+
+setTimeout(function() {
+	// click key again
+	document.dispatchEvent(ev);
+	document.dispatchEvent(ev);
+}, 250);
+</script>
+<img src="/delay?delay=3000&amp;file=assets/img.jpg" width="200" height="10000" />
+<%= footer %>

tests/page-templates/21-continuity/45-interaction-no-eventtiming.js

@@ -0,0 +1,66 @@
+/*eslint-env mocha*/
+/*global BOOMR_test,assert*/
+
+const {assert} = require("chai");
+
+describe("e2e/21-continuity/45-interaction-no-eventtiming", function() {
+	var tf = BOOMR.plugins.TestFramework;
+	var t = BOOMR_test;
+
+	it("Should have sent a single beacon validation", function(done) {
+		t.validateBeaconWasSent(done);
+	});
+
+	it("Should not have the EventTiming plugin", function(done) {
+		assert.isUndefined(BOOMR.plugins.EventTiming);
+	});
+
+	it("Should have sent the Time to First Interaction (c.ttfi)", function() {
+		var b = tf.lastBeacon();
+
+		assert.isDefined(b["c.ttfi"]);
+		var ttfi = parseInt(b["c.ttfi"], 10);
+
+		if (t.isNavigationTimingSupported()) {
+			var st = parseInt(b["rt.tstart"], 10);
+			assert.closeTo(st + ttfi, window.ttfi, 20);
+		}
+		else {
+			assert.operator(ttfi, ">=", 0);
+		}
+	});
+
+	it("Should have the interaction timeline (c.t.inter)", function() {
+		var b = tf.lastBeacon();
+
+		assert.isDefined(b["c.t.inter"]);
+		assert.operator(b["c.t.inter"].length, ">=", 1);
+	});
+
+	it("Could have the interaction delay timeline (c.t.interdly)", function() {
+		var b = tf.lastBeacon();
+
+		if (b["c.i.a"]) {
+			assert.isDefined(b["c.t.interdly"]);
+			assert.operator(b["c.t.interdly"].length, ">=", 1);
+		}
+	});
+
+	it("Could have interaction delay metrics (c.i.a, c.i.dc and c.i.dt)", function() {
+		var b = tf.lastBeacon();
+
+		if (!b["c.i.a"]) {
+			assert.operator(parseInt(b["c.i.a"], 10), ">=", 1);
+			assert.operator(parseInt(b["c.i.dc"], 10), ">=", 1);
+			assert.operator(parseInt(b["c.i.dc"], 10), "<=", 10);
+			assert.operator(parseInt(b["c.i.dt"], 10), ">=", 1);
+		}
+	});
+
+	it("Should have First Input Delay (c.fid)", function() {
+		var b = tf.lastBeacon();
+
+		assert.isDefined(b["c.fid"]);
+		assert.operator(parseInt(b["c.fid"], 10), ">=", 19);  // we had a 20ms busy wait, allow for some fuzzing
+	});
+});