Merge pull request #789 from NativeScript/flaky-time

__time tests seem flaky, add 5 attempts in the test to ensure they won't fail because of GC

Author: PanayotCankov

test-app/app/src/main/assets/app/tests/testRuntimeImplementedAPIs.js

@@ -1,18 +1,30 @@
 describe("Runtime exposes", function () {
   it("__time a low overhead, high resolution, time in ms.", function() {
-    var dateTimeStart = Date.now();
-    var timeStart = __time();
-    var acc = 0;
-    var s = android.os.SystemClock.elapsedRealtime();
-    for (var i = 0; i < 1000; i++) {
-      var c = android.os.SystemClock.elapsedRealtime();
-      acc += (c - s);
-      s = c;
+    // Try to get the times using Date.now and __time and compare the results, expect them to be somewhat "close".
+    // Sometimes GC hits after Date.now is captured but before __time or the vice-versa and the test fails,
+    // so we are giving it several attempts.
+    for(var i = 0; i < 5; i++) {
+      try {
+        var dateTimeStart = Date.now();
+        var timeStart = __time();
+        var acc = 0;
+        var s = android.os.SystemClock.elapsedRealtime();
+        for (var i = 0; i < 1000; i++) {
+          var c = android.os.SystemClock.elapsedRealtime();
+          acc += (c - s);
+          s = c;
+        }
+        var dateTimeEnd = Date.now();
+        var timeEnd = __time();
+        var dateDelta = dateTimeEnd - dateTimeStart;
+        var timeDelta = timeEnd - timeStart;
+        expect(Math.abs(dateDelta - timeDelta) < dateDelta * 0.25).toBe(true);
+        break;
+      } catch(e) {
+        if (i == 4) {
+          throw e;
+        }
+      }
     }
-    var dateTimeEnd = Date.now();
-    var timeEnd = __time();
-    var dateDelta = dateTimeEnd - dateTimeStart;
-    var timeDelta = timeEnd - timeStart;
-    expect(Math.abs(dateDelta - timeDelta) < dateDelta * 0.25).toBe(true);
   });
 });