Changes to observer

Author: gthea

src/androidTest/java/io/split/android/client/service/impressions/observer/ImpressionsObserverTest.java

@@ -170,6 +170,23 @@ public void persistCallsPersistOnStorage() {
         verify(cache).persist();
     }
 
+    @Test
+    public void previousTimeIsAlwaysNullWhenImpressionHasProperties() {
+        ImpressionsObserver observer = new ImpressionsObserverImpl(mStorage, 1);
+        Impression i = new Impression("key",
+                null,
+                "feature",
+                "on",
+                System.currentTimeMillis(),
+                "label",
+                1234567L,
+                null,
+                "{\"key\":\"value\"}");
+        for (int j = 0; j < 10; j++) {
+            assertNull(observer.testAndSet(i));
+        }
+    }
+
     private void caller(ImpressionsObserver o, int count, ConcurrentLinkedQueue<Impression> imps) {
 
         while (count-- > 0) {

src/main/java/io/split/android/client/service/impressions/observer/ImpressionsObserverImpl.java

@@ -27,6 +27,10 @@ public Long testAndSet(Impression impression) {
         if (null == impression) {
             return null;
         }
+        final String properties = impression.properties();
+        if (properties != null && !properties.isEmpty()) {
+            return null;
+        }
 
         Long hash = ImpressionHasher.process(impression);
         @Nullable