diff --git a/robolectric_tests/src/com/android/customization/model/clock/ClockManagerTest.java b/robolectric_tests/src/com/android/customization/model/clock/ClockManagerTest.java
index 11552de..f431006 100644
--- a/robolectric_tests/src/com/android/customization/model/clock/ClockManagerTest.java
+++ b/robolectric_tests/src/com/android/customization/model/clock/ClockManagerTest.java
@@ -19,6 +19,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 import android.content.ContentResolver;
 import android.provider.Settings.Secure;
@@ -43,11 +44,14 @@
 
     private static final String CLOCK_ID = "id";
     private static final String CLOCK_FIELD = "clock";
+    private static final String CLOCK_FACE_SETTING = "fake_clock_face_setting";
 
     @Mock ClockProvider mProvider;
     @Mock ThemesUserEventLogger mLogger;
     private ContentResolver mContentResolver;
     private ClockManager mManager;
+    @Mock private Clockface mMockClockface;
+    @Mock private Callback mMockCallback;
 
     @Before
     public void setUp() {
@@ -81,10 +85,48 @@
     }
 
     @Test
-    public void testGetCurrentClock() {
-        // GIVEN that secure settings contains a clock id
-        Secure.putString(mContentResolver, ClockManager.CLOCK_FACE_SETTING, CLOCK_ID);
-        // THEN the current clock is that id
+    public void testApply_whenJSONExceptionOccurs_callsOnError() {
+        when(mMockClockface.getId()).thenThrow(JSONException.class);
+
+        mManager.apply(mMockClockface, mMockCallback);
+
+        verify(mMockCallback).onError(null);
+    }
+
+    @Test
+    public void testGetCurrentClock_returnsClockId() throws JSONException {
+        // Secure settings contains a clock id
+        JSONObject json = new JSONObject().put(CLOCK_FIELD, CLOCK_ID);
+        Secure.putString(mContentResolver, ClockManager.CLOCK_FACE_SETTING, json.toString());
+
+        // The current clock is that id
         assertEquals(CLOCK_ID, mManager.getCurrentClock());
     }
+
+    @Test
+    public void testGetCurrentClock_whenJSONExceptionOccurs_returnsClockFaceSetting() {
+        // Secure settings contains a clock face setting with invalid format to cause JSONException.
+        Secure.putString(mContentResolver, ClockManager.CLOCK_FACE_SETTING, CLOCK_FACE_SETTING);
+
+        // The current clock is the clock face setting which is saved in secure settings.
+        assertEquals(CLOCK_FACE_SETTING, mManager.getCurrentClock());
+    }
+
+    @Test
+    public void testGetCurrentClock_withNullIdInSecureSettings_returnsNullId() {
+        // Secure settings contains a null clock id
+        Secure.putString(mContentResolver, ClockManager.CLOCK_FACE_SETTING, /* value= */ null);
+
+        // The current clock is null
+        assertEquals(null, mManager.getCurrentClock());
+    }
+
+    @Test
+    public void testGetCurrentClock_withEmptyIdInSecureSettings_returnsEmptyId() {
+        // Secure settings contains an empty clock id
+        Secure.putString(mContentResolver, ClockManager.CLOCK_FACE_SETTING, /* value= */ "");
+
+        // The current clock is empty
+        assertEquals("", mManager.getCurrentClock());
+    }
 }