adds custom telemetry timestamp test

Author: adnanyaqoobvirk

core/src/test/java/com/microsoft/applicationinsights/TelemetryClientTests.java

@@ -381,6 +381,15 @@ public void testTrackPageViewWithPageViewTelemetry() {
         verifyAndGetLastEventSent();
     }
 
+    @Test
+    public void testTrackWithCustomTelemetryTimestamp() {
+        Date timestamp = new Date(10000);
+        client.track(new RequestTelemetry("Name", timestamp, 1, "200", true));
+
+        Telemetry telemetry = verifyAndGetLastEventSent();
+        assertEquals(telemetry.getTimestamp(), timestamp);
+    }
+
     @Test
     public void testTrack() {
         TraceTelemetry telemetry = new TraceTelemetry("test");