diff --git a/robolectric_tests/src/com/android/customization/model/theme/ThemeManagerTest.java b/robolectric_tests/src/com/android/customization/model/theme/ThemeManagerTest.java
index 0a17b5b..6f1f95e 100644
--- a/robolectric_tests/src/com/android/customization/model/theme/ThemeManagerTest.java
+++ b/robolectric_tests/src/com/android/customization/model/theme/ThemeManagerTest.java
@@ -26,25 +26,28 @@
 import static com.android.customization.model.ResourceConstants.SYSUI_PACKAGE;
 import static com.android.customization.model.ResourceConstants.THEME_SETTING;
 
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.Assert.assertTrue;
 import static junit.framework.TestCase.assertEquals;
-import static junit.framework.TestCase.assertTrue;
 
-import static org.junit.Assert.assertFalse;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 import android.provider.Settings;
 
 import androidx.annotation.Nullable;
 import androidx.fragment.app.FragmentActivity;
 
+import com.android.customization.model.CustomizationManager.OptionsFetchedListener;
 import com.android.customization.model.CustomizationManager.Callback;
+import com.android.customization.model.theme.custom.CustomTheme;
 import com.android.customization.module.ThemesUserEventLogger;
 import com.android.customization.testutils.OverlayManagerMocks;
-import com.android.customization.testutils.Wait;
 import com.android.wallpaper.module.WallpaperSetter;
 
+import org.json.JSONObject;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -60,6 +63,7 @@
     @Mock OverlayManagerCompat mMockOm;
     @Mock WallpaperSetter mMockWallpaperSetter;
     @Mock ThemesUserEventLogger mThemesUserEventLogger;
+    @Mock ThemeBundleProvider mThemeBundleProvider;
     private OverlayManagerMocks mMockOmHelper;
     private ThemeManager mThemeManager;
     private FragmentActivity mActivity;
@@ -71,9 +75,8 @@
         mActivity = spy(activity);
         mMockOmHelper = new OverlayManagerMocks();
         mMockOmHelper.setUpMock(mMockOm);
-        ThemeBundleProvider provider = mock(ThemeBundleProvider.class);
-        mThemeManager = new ThemeManager(
-                provider, activity, mMockWallpaperSetter, mMockOm, mThemesUserEventLogger);
+        mThemeManager = new ThemeManager(mThemeBundleProvider, activity, mMockWallpaperSetter,
+                mMockOm, mThemesUserEventLogger);
     }
 
     @After
@@ -82,7 +85,7 @@
     }
 
     @Test
-    public void testApply_DefaultTheme() {
+    public void apply_WithDefaultTheme_StoresEmptyJsonString() {
         mMockOmHelper.addOverlay("test.package.name_color", ANDROID_PACKAGE,
                 OVERLAY_CATEGORY_COLOR, true, 0);
         mMockOmHelper.addOverlay("test.package.name_font", ANDROID_PACKAGE,
@@ -102,13 +105,94 @@
 
         applyTheme(defaultTheme);
 
-        assertEquals("Secure Setting should be emtpy after applying default theme",
-                "",
+        assertEquals("Secure Setting should be empty JSON string after applying default theme",
+                new JSONObject().toString(),
                 Settings.Secure.getString(mActivity.getContentResolver(), THEME_SETTING));
     }
 
     @Test
-    public void testApply_NonDefault() {
+    public void apply_WithOverlayTheme_StoresSerializedPackagesWithTimestamp() {
+        ThemeBundle theme = getOverlayTheme();
+        final String serializedPackagesWithTimestamp = theme.getSerializedPackagesWithTimestamp();
+
+        theme = spy(theme);
+        // Makes it return the fixed serializedPackagesWithTimestamp to test. Since we will get
+        // fresh time every time, it's hard to compare for testing.
+        when(theme.getSerializedPackagesWithTimestamp())
+                .thenReturn(serializedPackagesWithTimestamp);
+
+        applyTheme(theme);
+
+        assertEquals("Secure Setting should be the overlay packages after applying theme",
+                serializedPackagesWithTimestamp,
+                Settings.Secure.getString(mActivity.getContentResolver(), THEME_SETTING));
+    }
+
+    @Test
+    public void isAvailable_ThemeBundleProviderAndOverlayManagerAreAvailable_ReturnsTrue() {
+        when(mThemeBundleProvider.isAvailable()).thenReturn(true);
+        when(mMockOm.isAvailable()).thenReturn(true);
+
+        assertTrue(mThemeManager.isAvailable());
+    }
+
+    @Test
+    public void isAvailable_ThemeBundleProviderOrOverlayManagerIsAvailable_ReturnsFalse() {
+        when(mThemeBundleProvider.isAvailable()).thenReturn(false);
+        when(mMockOm.isAvailable()).thenReturn(true);
+        assertFalse(mThemeManager.isAvailable());
+
+        when(mThemeBundleProvider.isAvailable()).thenReturn(true);
+        when(mMockOm.isAvailable()).thenReturn(false);
+        assertFalse(mThemeManager.isAvailable());
+    }
+
+    @Test
+    public void fetchOptions_ThemeBundleProviderFetches() {
+        OptionsFetchedListener listener = mock(OptionsFetchedListener.class);
+
+        mThemeManager.fetchOptions(listener, false);
+
+        verify(mThemeBundleProvider).fetch(listener, false);
+    }
+
+    @Test
+    public void removeCustomTheme_ThemeBundleProviderRemovesCustomTheme() {
+        CustomTheme customTheme = mock(CustomTheme.class);
+        mThemeManager.removeCustomTheme(customTheme);
+
+        verify(mThemeBundleProvider).removeCustomTheme(customTheme);
+    }
+
+    @Test
+    public void findThemeByPackages_ThemeBundleProviderFindsEquivalent() {
+        CustomTheme theme = mock(CustomTheme.class);
+        mThemeManager.findThemeByPackages(theme);
+
+        verify(mThemeBundleProvider).findEquivalent(theme);
+    }
+
+    @Test
+    public void storeEmptyTheme_SettingsSecureStoresEmptyTheme() {
+        mThemeManager.storeEmptyTheme();
+
+        assertEquals(
+                new JSONObject().toString(),
+                Settings.Secure.getString(mActivity.getContentResolver(), THEME_SETTING));
+    }
+
+    @Test
+    public void getStoredOverlays_GetsFromSettingsSecureWithExpectedName() {
+        ThemeBundle theme = getOverlayTheme();
+
+        applyTheme(theme);
+
+        assertEquals(
+                Settings.Secure.getString(mActivity.getContentResolver(), THEME_SETTING),
+                mThemeManager.getStoredOverlays());
+    }
+
+    private ThemeBundle getOverlayTheme() {
         final String bundleColorPackage = "test.package.name_color";
         final String bundleFontPackage = "test.package.name_font";
         final String otherPackage = "other.package.name_font";
@@ -120,16 +204,10 @@
         mMockOmHelper.addOverlay(otherPackage, ANDROID_PACKAGE,
                 OVERLAY_CATEGORY_FONT, false, 0);
 
-        ThemeBundle theme = new ThemeBundle.Builder()
+        return new ThemeBundle.Builder()
                 .addOverlayPackage(OVERLAY_CATEGORY_COLOR, bundleColorPackage)
                 .addOverlayPackage(OVERLAY_CATEGORY_FONT, bundleFontPackage)
                 .build(mActivity);
-
-        applyTheme(theme);
-
-        assertEquals("Secure Setting was not properly set after applying theme",
-                theme.getSerializedPackages(),
-                Settings.Secure.getString(mActivity.getContentResolver(), THEME_SETTING));
     }
 
     private void applyTheme(ThemeBundle theme) {