Test: added a way to do time mock testing

zeh · Dec 14, 2018 · c9fcbc2 · c9fcbc2
1 parent 710f00b
commit c9fcbc2
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Showing 4 changed files with 84 additions and 0 deletions.
diff --git a/.gitignore b/.gitignore
@@ -9,3 +9,4 @@ dist
 node_modules
 npm-debug.log
 temp
+yarn-error.log
diff --git a/package.json b/package.json
@@ -38,6 +38,7 @@
   "babel-core": "7.0.0-bridge.0",
   "babel-jest": "^23.6.0",
   "jest": "^23.6.0",
+  "mockdate": "^2.0.2",
   "rimraf": "^2.6.2",
   "rollup": "^0.67.4",
   "rollup-plugin-node-resolve": "^4.0.0",

diff --git a/test/unit/utils/timeMock.js b/test/unit/utils/timeMock.js
@@ -0,0 +1,77 @@
+import MockDate from "mockdate";
+
+const originalRequestAnimationFrame = global.requestAnimationFrame;
+const originalCancelAnimationFrame = global.cancelAnimationFrame;
+
+let enabled = false;
+
+/**
+ * Disable requestAnimationFrame() and use timers
+ * Then we can use:
+ * - jest.useFakeTimers()
+ * - jest.runAllTimers()
+ * - jest.runOnlyPendingTimers()
+ * - jest.advanceTimersByTime()
+ * - jest.clearAllTimers()
+ * to simulate time.
+ */
+export function enableTimeMocks() {
+	// Ensure requestAnimationFrame() uses time functions
+	if (!enabled) {
+		useFixedTime();
+
+		let lastTime = 0;
+		enabled = true;
+		global.requestAnimationFrame = callback => {
+			const currTime = new Date().getTime();
+			const timeToCall = Math.max(0, 16 - (currTime - lastTime));
+			const id = setTimeout(() => {
+				callback(currTime + timeToCall);
+			}, timeToCall);
+			lastTime = currTime + timeToCall;
+			return id;
+		};
+
+		global.cancelAnimationFrame = function(id) {
+			clearTimeout(id);
+		};
+
+		// Enable fake timers on jest
+		jest.useFakeTimers();
+
+		timeTravel(0);
+	}
+}
+
+export function timeTravel(durationMs, step = 100) {
+	if (enabled) {
+		const tickTravel = tickDurationMs => {
+			jest.advanceTimersByTime(tickDurationMs);
+			const now = Date.now();
+			MockDate.set(new Date(now + tickDurationMs));
+		};
+
+		let done = 0;
+		while (durationMs - done > step) {
+			tickTravel(step);
+			done += step;
+		}
+		tickTravel(durationMs - done);
+	}
+}
+
+export function disableTimeMocks() {
+	if (enabled) {
+		enabled = false;
+
+		jest.clearAllTimers();
+		jest.useRealTimers();
+
+		global.requestAnimationFrame = originalRequestAnimationFrame;
+		global.cancelAnimationFrame = originalCancelAnimationFrame;
+	}
+}
+
+export function useFixedTime() {
+	MockDate.set(1540326022034);
+}
diff --git a/yarn.lock b/yarn.lock
@@ -2962,6 +2962,11 @@ mkdirp@^0.5.0, mkdirp@^0.5.1:
   dependencies:
     minimist "0.0.8"
 
+mockdate@^2.0.2:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/mockdate/-/mockdate-2.0.2.tgz#5ae0c0eaf8fe23e009cd01f9889b42c4f634af12"
+  integrity sha1-WuDA6vj+I+AJzQH5iJtCxPY0rxI=
+
 moremath@^2.0.2:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/moremath/-/moremath-2.0.2.tgz#d3574121e2084d4645ab6c9ba7d253e72b11fece"