Fix null ptr in test cases by supplying a test adapter.

Change-Id: If979703d1140f8ad74b2896825a6b490af746442
diff --git a/tests/src/com/android/ex/chips/ChipsTest.java b/tests/src/com/android/ex/chips/ChipsTest.java
index 4d662f3..6639bcb 100644
--- a/tests/src/com/android/ex/chips/ChipsTest.java
+++ b/tests/src/com/android/ex/chips/ChipsTest.java
@@ -119,9 +119,16 @@
         }
     }
 
+    private class TestBaseRecipientAdapter extends BaseRecipientAdapter {
+        public TestBaseRecipientAdapter(Context context) {
+            super(context);
+        }
+    }
+
     private MockRecipientEditTextView createViewForTesting() {
         mEditable = new SpannableStringBuilder();
         MockRecipientEditTextView view = new MockRecipientEditTextView(getContext());
+        view.setAdapter(new TestBaseRecipientAdapter(getContext()));
         return view;
     }