From 2631d09367bf3312e5f7331f81b36f0928e8f676 Mon Sep 17 00:00:00 2001
From: Leo <39062083+lsirac@users.noreply.github.com>
Date: Fri, 29 Jun 2018 09:25:55 -0700
Subject: [PATCH] Adds continue as guest (#1375)

---
 .../firebase/uidemo/auth/AuthUiActivity.java  |  5 +
 .../uidemo/auth/SignedInActivity.java         |  2 +-
 app/src/main/res/layout/auth_ui_layout.xml    | 13 ++-
 app/src/main/res/values/strings.xml           |  1 +
 auth/README.md                                |  3 +-
 .../java/com/firebase/ui/auth/AuthUI.java     | 34 ++++++-
 .../data/remote/AnonymousSignInHandler.java   | 79 +++++++++++++++
 .../auth/ui/idp/AuthMethodPickerActivity.java | 15 ++-
 .../drawable/fui_ic_anonymous_white_24dp.xml  | 12 +++
 .../fui_idp_button_background_anonymous.xml   | 19 ++++
 .../layout/fui_provider_button_anonymous.xml  |  6 ++
 auth/src/main/res/values/colors.xml           |  1 +
 auth/src/main/res/values/strings.xml          |  1 +
 auth/src/main/res/values/styles.xml           |  6 ++
 .../java/com/firebase/ui/auth/AuthUITest.java | 18 +++-
 .../ui/auth/testhelpers/TestHelper.java       |  3 +
 .../ui/idp/AuthMethodPickerActivityTest.java  |  8 +-
 .../viewmodel/AnonymousSignInHandlerTest.java | 98 +++++++++++++++++++
 ...kingSocialProviderResponseHandlerTest.java |  2 -
 library/quality/lint-baseline.xml             |  1 -
 20 files changed, 308 insertions(+), 19 deletions(-)
 create mode 100644 auth/src/main/java/com/firebase/ui/auth/data/remote/AnonymousSignInHandler.java
 create mode 100644 auth/src/main/res/drawable/fui_ic_anonymous_white_24dp.xml
 create mode 100644 auth/src/main/res/drawable/fui_idp_button_background_anonymous.xml
 create mode 100644 auth/src/main/res/layout/fui_provider_button_anonymous.xml
 create mode 100644 auth/src/test/java/com/firebase/ui/auth/viewmodel/AnonymousSignInHandlerTest.java

diff --git a/app/src/main/java/com/firebase/uidemo/auth/AuthUiActivity.java b/app/src/main/java/com/firebase/uidemo/auth/AuthUiActivity.java
index c1aeb0632..ca68daab9 100644
--- a/app/src/main/java/com/firebase/uidemo/auth/AuthUiActivity.java
+++ b/app/src/main/java/com/firebase/uidemo/auth/AuthUiActivity.java
@@ -70,6 +70,7 @@ public class AuthUiActivity extends AppCompatActivity {
     @BindView(R.id.github_provider) CheckBox mUseGitHubProvider;
     @BindView(R.id.email_provider) CheckBox mUseEmailProvider;
     @BindView(R.id.phone_provider) CheckBox mUsePhoneProvider;
+    @BindView(R.id.anonymous_provider) CheckBox mUseAnonymousProvider;
 
     @BindView(R.id.default_theme) RadioButton mDefaultTheme;
     @BindView(R.id.green_theme) RadioButton mGreenTheme;
@@ -319,6 +320,10 @@ private List<IdpConfig> getSelectedProviders() {
             selectedProviders.add(new IdpConfig.PhoneBuilder().build());
         }
 
+        if (mUseAnonymousProvider.isChecked()) {
+            selectedProviders.add(new IdpConfig.AnonymousBuilder().build());
+        }
+
         return selectedProviders;
     }
 
diff --git a/app/src/main/java/com/firebase/uidemo/auth/SignedInActivity.java b/app/src/main/java/com/firebase/uidemo/auth/SignedInActivity.java
index f921f310c..833ca3f5f 100644
--- a/app/src/main/java/com/firebase/uidemo/auth/SignedInActivity.java
+++ b/app/src/main/java/com/firebase/uidemo/auth/SignedInActivity.java
@@ -164,7 +164,7 @@ private void populateProfile(@Nullable IdpResponse response) {
 
         List<String> providers = new ArrayList<>();
         if (user.getProviderData().isEmpty()) {
-            providers.add("Anonymous");
+            providers.add(getString(R.string.providers_anonymous));
         } else {
             for (UserInfo info : user.getProviderData()) {
                 switch (info.getProviderId()) {
diff --git a/app/src/main/res/layout/auth_ui_layout.xml b/app/src/main/res/layout/auth_ui_layout.xml
index 913a58d38..c16c150d1 100644
--- a/app/src/main/res/layout/auth_ui_layout.xml
+++ b/app/src/main/res/layout/auth_ui_layout.xml
@@ -34,8 +34,8 @@
                 style="@style/Widget.AppCompat.Button.Colored"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_gravity="center"
                 android:layout_marginTop="16dp"
+                android:layout_gravity="center"
                 android:text="@string/sign_in_start" />
 
             <Button
@@ -43,8 +43,8 @@
                 style="@style/Widget.AppCompat.Button.Colored"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_gravity="center"
                 android:layout_marginBottom="16dp"
+                android:layout_gravity="center"
                 android:text="@string/sign_in_silent" />
 
             <TextView
@@ -80,7 +80,7 @@
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:checked="true"
-                android:text="@string/providers_github"/>
+                android:text="@string/providers_github" />
 
             <CheckBox
                 android:id="@+id/email_provider"
@@ -96,6 +96,13 @@
                 android:checked="true"
                 android:text="@string/providers_phone" />
 
+            <CheckBox
+                android:id="@+id/anonymous_provider"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:checked="true"
+                android:text="@string/providers_anonymous" />
+
             <TextView
                 style="@style/Base.TextAppearance.AppCompat.Subhead"
                 android:layout_width="wrap_content"
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 21f8093f3..c500e7614 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -27,6 +27,7 @@
     <string name="providers_twitter">Twitter</string>
     <string name="providers_email">Email</string>
     <string name="providers_phone">Phone</string>
+    <string name="providers_anonymous">Anonymous</string>
 
     <string name="theme_header">Theme</string>
     <string name="theme_default">Default theme</string>
diff --git a/auth/README.md b/auth/README.md
index 366635065..c59046b68 100644
--- a/auth/README.md
+++ b/auth/README.md
@@ -328,7 +328,8 @@ startActivityForResult(
                         new AuthUI.IdpConfig.TwitterBuilder().build(),
                         new AuthUI.IdpConfig.GitHubBuilder().build(),
                         new AuthUI.IdpConfig.EmailBuilder().build(),
-                        new AuthUI.IdpConfig.PhoneBuilder().build()))
+                        new AuthUI.IdpConfig.PhoneBuilder().build(),
+                        new AuthUI.IdpConfig.AnonymousBuilder().build()))
                 .build(),
         RC_SIGN_IN);
 ```
diff --git a/auth/src/main/java/com/firebase/ui/auth/AuthUI.java b/auth/src/main/java/com/firebase/ui/auth/AuthUI.java
index f7844a78b..2ba5c6a05 100644
--- a/auth/src/main/java/com/firebase/ui/auth/AuthUI.java
+++ b/auth/src/main/java/com/firebase/ui/auth/AuthUI.java
@@ -95,13 +95,20 @@ public final class AuthUI {
     @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
     public static final String TAG = "AuthUI";
 
+    /**
+     * Provider for anonymous users.
+     */
+    @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
+    public static final String ANONYMOUS_PROVIDER = "anonymous";
+
     @StringDef({
                        GoogleAuthProvider.PROVIDER_ID,
                        FacebookAuthProvider.PROVIDER_ID,
                        TwitterAuthProvider.PROVIDER_ID,
                        GithubAuthProvider.PROVIDER_ID,
                        EmailAuthProvider.PROVIDER_ID,
-                       PhoneAuthProvider.PROVIDER_ID
+                       PhoneAuthProvider.PROVIDER_ID,
+                       ANONYMOUS_PROVIDER
                })
     @Retention(RetentionPolicy.SOURCE)
     public @interface SupportedProvider {}
@@ -121,7 +128,8 @@ public final class AuthUI {
                     TwitterAuthProvider.PROVIDER_ID,
                     GithubAuthProvider.PROVIDER_ID,
                     EmailAuthProvider.PROVIDER_ID,
-                    PhoneAuthProvider.PROVIDER_ID
+                    PhoneAuthProvider.PROVIDER_ID,
+                    ANONYMOUS_PROVIDER
             )));
 
     /**
@@ -990,6 +998,15 @@ public GitHubBuilder setPermissions(@NonNull List<String> permissions) {
                 return this;
             }
         }
+
+        /**
+         * {@link IdpConfig} builder for the Anonymous provider.
+         */
+        public static final class AnonymousBuilder extends Builder {
+            public AnonymousBuilder() {
+                super(ANONYMOUS_PROVIDER);
+            }
+        }
     }
 
     /**
@@ -1066,7 +1083,8 @@ public T setTosAndPrivacyPolicyUrls(@NonNull String tosUrl,
 
         /**
          * Specified the set of supported authentication providers. At least one provider must
-         * be specified. There may only be one instance of each provider.
+         * be specified. There may only be one instance of each provider. Anonymous provider cannot
+         * be the only provider specified.
          * <p>
          * <p>If no providers are explicitly specified by calling this method, then the email
          * provider is the default supported provider.
@@ -1074,9 +1092,19 @@ public T setTosAndPrivacyPolicyUrls(@NonNull String tosUrl,
          * @param idpConfigs a list of {@link IdpConfig}s, where each {@link IdpConfig} contains the
          *                   configuration parameters for the IDP.
          * @see IdpConfig
+         *
+         * @throws IllegalStateException if anonymous provider is the only specified provider.
          */
         @NonNull
         public T setAvailableProviders(@NonNull List<IdpConfig> idpConfigs) {
+            Preconditions.checkNotNull(idpConfigs, "idpConfigs cannot be null");
+            if (idpConfigs.size() == 1 &&
+                    idpConfigs.get(0).getProviderId().equals(ANONYMOUS_PROVIDER)) {
+                throw new IllegalStateException("Sign in as guest cannot be the only sign in " +
+                        "method. In this case, sign the user in anonymously your self; " +
+                        "no UI is needed.");
+            }
+
             mProviders.clear();
 
             for (IdpConfig config : idpConfigs) {
diff --git a/auth/src/main/java/com/firebase/ui/auth/data/remote/AnonymousSignInHandler.java b/auth/src/main/java/com/firebase/ui/auth/data/remote/AnonymousSignInHandler.java
new file mode 100644
index 000000000..5e3f771c4
--- /dev/null
+++ b/auth/src/main/java/com/firebase/ui/auth/data/remote/AnonymousSignInHandler.java
@@ -0,0 +1,79 @@
+package com.firebase.ui.auth.data.remote;
+
+import android.app.Application;
+import android.content.Intent;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.annotation.RestrictTo;
+import android.support.annotation.VisibleForTesting;
+
+import com.firebase.ui.auth.AuthUI;
+import com.firebase.ui.auth.IdpResponse;
+import com.firebase.ui.auth.data.model.FlowParameters;
+import com.firebase.ui.auth.data.model.Resource;
+import com.firebase.ui.auth.data.model.User;
+import com.firebase.ui.auth.ui.HelperActivityBase;
+import com.firebase.ui.auth.viewmodel.ProviderSignInBase;
+import com.google.android.gms.tasks.OnFailureListener;
+import com.google.android.gms.tasks.OnSuccessListener;
+import com.google.firebase.FirebaseApp;
+import com.google.firebase.auth.AuthResult;
+import com.google.firebase.auth.FirebaseAuth;
+
+
+@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
+public class AnonymousSignInHandler extends ProviderSignInBase<FlowParameters> {
+
+    @VisibleForTesting
+    public FirebaseAuth mAuth;
+
+    public AnonymousSignInHandler(Application application) {
+        super(application);
+    }
+
+    @Override
+    protected void onCreate() {
+        mAuth = getAuth();
+    }
+
+    @Override
+    public void startSignIn(@NonNull HelperActivityBase activity) {
+        setResult(Resource.<IdpResponse>forLoading());
+
+        // Calling signInAnonymously() will always return the same anonymous user if already
+        // available. This is enforced by the client SDK.
+        mAuth.signInAnonymously()
+                .addOnSuccessListener(new OnSuccessListener<AuthResult>() {
+                    @Override
+                    public void onSuccess(AuthResult result) {
+                        setResult(Resource.<IdpResponse>forSuccess(initResponse(
+                                result.getAdditionalUserInfo().isNewUser())));
+                    }
+                })
+                .addOnFailureListener(new OnFailureListener() {
+                    @Override
+                    public void onFailure(@NonNull Exception e) {
+                        setResult(Resource.<IdpResponse>forFailure(e));
+                    }
+                });
+
+    }
+
+    @Override
+    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {}
+
+    private IdpResponse initResponse(boolean isNewUser) {
+        return new IdpResponse.Builder(
+                new User.Builder(AuthUI.ANONYMOUS_PROVIDER, null)
+                        .build())
+                .setNewUser(isNewUser)
+                .build();
+    }
+
+    // TODO: We need to centralize the auth logic. ProviderSignInBase classes were originally
+    // meant to only retrieve remote provider data.
+    private FirebaseAuth getAuth() {
+        FirebaseApp app = FirebaseApp.getInstance(getArguments().appName);
+        return FirebaseAuth.getInstance(app);
+    }
+}
diff --git a/auth/src/main/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivity.java b/auth/src/main/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivity.java
index f0d35c160..e036e70b6 100644
--- a/auth/src/main/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivity.java
+++ b/auth/src/main/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivity.java
@@ -41,6 +41,7 @@
 import com.firebase.ui.auth.R;
 import com.firebase.ui.auth.data.model.FlowParameters;
 import com.firebase.ui.auth.data.model.UserCancellationException;
+import com.firebase.ui.auth.data.remote.AnonymousSignInHandler;
 import com.firebase.ui.auth.data.remote.EmailSignInHandler;
 import com.firebase.ui.auth.data.remote.FacebookSignInHandler;
 import com.firebase.ui.auth.data.remote.GitHubSignInHandler;
@@ -117,7 +118,7 @@ protected void onFailure(@NonNull Exception e) {
                 if (e instanceof FirebaseAuthAnonymousUpgradeException) {
                     finish(ErrorCodes.ANONYMOUS_UPGRADE_MERGE_CONFLICT,
                             ((FirebaseAuthAnonymousUpgradeException) e).getResponse().toIntent());
-                } else if ( (!(e instanceof UserCancellationException))) {
+                } else if ((!(e instanceof UserCancellationException))) {
                     String text = e instanceof FirebaseUiException ? e.getMessage() :
                             getString(R.string.fui_error_unknown);
                     Toast.makeText(AuthMethodPickerActivity.this,
@@ -186,6 +187,13 @@ private void populateIdpList(List<IdpConfig> providerConfigs,
 
                     buttonLayout = R.layout.fui_provider_button_phone;
                     break;
+                case AuthUI.ANONYMOUS_PROVIDER:
+                    AnonymousSignInHandler anonymous = supplier.get(AnonymousSignInHandler.class);
+                    anonymous.init(getFlowParams());
+                    provider = anonymous;
+
+                    buttonLayout = R.layout.fui_provider_button_anonymous;
+                    break;
                 default:
                     throw new IllegalStateException("Unknown provider: " + providerId);
             }
@@ -215,8 +223,9 @@ private void handleResponse(@NonNull IdpResponse response) {
                         // started.
                         handler.startSignIn(response);
                     } else {
-                        // Email or phone: the credentials should have already been saved so simply
-                        // move along.
+                        // Email or phone: the credentials should have already been saved so
+                        // simply move along. Anononymous sign in also does not require any
+                        // other operations.
                         finish(response.isSuccessful() ? RESULT_OK : RESULT_CANCELED,
                                 response.toIntent());
                     }
diff --git a/auth/src/main/res/drawable/fui_ic_anonymous_white_24dp.xml b/auth/src/main/res/drawable/fui_ic_anonymous_white_24dp.xml
new file mode 100644
index 000000000..212818c29
--- /dev/null
+++ b/auth/src/main/res/drawable/fui_ic_anonymous_white_24dp.xml
@@ -0,0 +1,12 @@
+<vector
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportHeight="24.0"
+    android:viewportWidth="24.0"
+    tools:ignore="InvalidVectorPath">
+    <path
+        android:fillColor="#FFFFFF"
+        android:pathData="M12 5.9c1.16 0 2.1.94 2.1 2.1s-0.94 2.1-2.1 2.1S9.9 9.16 9.9 8s0.94-2.1 2.1-2.1m0 9c2.97 0 6.1 1.46 6.1 2.1v1.1H5.9V17c0-0.64 3.13-2.1 6.1-2.1M12 4C9.79 4 8 5.79 8 8s1.79 4 4 4 4-1.79 4-4-1.79-4-4-4zm0 9c-2.67 0-8 1.34-8 4v3h16v-3c0-2.66-5.33-4-8-4z" />
+</vector>
diff --git a/auth/src/main/res/drawable/fui_idp_button_background_anonymous.xml b/auth/src/main/res/drawable/fui_idp_button_background_anonymous.xml
new file mode 100644
index 000000000..19bf89f26
--- /dev/null
+++ b/auth/src/main/res/drawable/fui_idp_button_background_anonymous.xml
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item>
+        <shape android:shape="rectangle">
+            <corners android:radius="3dp" />
+            <solid android:color="@color/fui_buttonShadow" />
+        </shape>
+    </item>
+    <item
+        android:bottom="@dimen/fui_button_inset_bottom"
+        android:left="@dimen/fui_button_inset_left"
+        android:right="@dimen/fui_button_inset_right"
+        android:top="@dimen/fui_button_inset_top">
+        <shape android:shape="rectangle">
+            <corners android:radius="3dp" />
+            <solid android:color="@color/fui_bgAnonymous" />
+        </shape>
+    </item>
+</layer-list>
diff --git a/auth/src/main/res/layout/fui_provider_button_anonymous.xml b/auth/src/main/res/layout/fui_provider_button_anonymous.xml
new file mode 100644
index 000000000..361d3c007
--- /dev/null
+++ b/auth/src/main/res/layout/fui_provider_button_anonymous.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.firebase.ui.auth.util.ui.SupportVectorDrawablesButton
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/anonymous_button"
+    style="@style/FirebaseUI.Button.AccountChooser.AnonymousButton"
+    android:text="@string/fui_sign_in_anonymously" />
diff --git a/auth/src/main/res/values/colors.xml b/auth/src/main/res/values/colors.xml
index 8b1a63aed..f3d1c1e74 100644
--- a/auth/src/main/res/values/colors.xml
+++ b/auth/src/main/res/values/colors.xml
@@ -14,5 +14,6 @@
     <color name="fui_bgGitHub">#24292E</color>
     <color name="fui_bgEmail">#D0021B</color>
     <color name="fui_bgPhone">#43C5A5</color>
+    <color name="fui_bgAnonymous">#f4b400</color>
     <color name="fui_buttonShadow">#64BEBEBE</color>
 </resources>
diff --git a/auth/src/main/res/values/strings.xml b/auth/src/main/res/values/strings.xml
index 1bc3a55e9..8eab9e43e 100644
--- a/auth/src/main/res/values/strings.xml
+++ b/auth/src/main/res/values/strings.xml
@@ -21,6 +21,7 @@
     <string name="fui_sign_in_with_github" translation_description="Sign in button text">Sign in with GitHub</string>
     <string name="fui_sign_in_with_email" translation_description="Sign in button text">Sign in with email</string>
     <string name="fui_sign_in_with_phone" translation_description="Sign in button text">Sign in with phone</string>
+    <string name="fui_sign_in_anonymously" translation_description="Continue as guest">Continue as guest</string>
 
     <!-- Email common-->
     <string name="fui_next_default" translation_description="Button text to continue">Next</string>
diff --git a/auth/src/main/res/values/styles.xml b/auth/src/main/res/values/styles.xml
index ce2877137..8a2d661f5 100644
--- a/auth/src/main/res/values/styles.xml
+++ b/auth/src/main/res/values/styles.xml
@@ -236,6 +236,12 @@
         <item name="android:textColor">#ffffff</item>
     </style>
 
+    <style name="FirebaseUI.Button.AccountChooser.AnonymousButton">
+        <item name="drawableStartCompat">@drawable/fui_ic_anonymous_white_24dp</item>
+        <item name="android:background">@drawable/fui_idp_button_background_anonymous</item>
+        <item name="android:textColor">#ffffff</item>
+    </style>
+
     <style name="FirebaseUI.TopProgressBar" parent="@style/Widget.MaterialProgressBar.ProgressBar.Horizontal">
         <item name="android:layout_width">match_parent</item>
         <item name="android:layout_height">4dp</item>
diff --git a/auth/src/test/java/com/firebase/ui/auth/AuthUITest.java b/auth/src/test/java/com/firebase/ui/auth/AuthUITest.java
index e359e5a1b..b11994a10 100644
--- a/auth/src/test/java/com/firebase/ui/auth/AuthUITest.java
+++ b/auth/src/test/java/com/firebase/ui/auth/AuthUITest.java
@@ -69,12 +69,13 @@ public void testCreatingStartIntent() {
                 .setAvailableProviders(Arrays.asList(
                         new IdpConfig.EmailBuilder().build(),
                         new IdpConfig.GoogleBuilder().build(),
-                        new IdpConfig.FacebookBuilder().build()))
+                        new IdpConfig.FacebookBuilder().build(),
+                        new IdpConfig.AnonymousBuilder().build()))
                 .setTosAndPrivacyPolicyUrls(TestConstants.TOS_URL, TestConstants.PRIVACY_URL)
                 .build()
                 .getParcelableExtra(ExtraConstants.FLOW_PARAMS);
 
-        assertEquals(3, flowParameters.providerInfo.size());
+        assertEquals(4, flowParameters.providerInfo.size());
         assertEquals(TestHelper.MOCK_APP.getName(), flowParameters.appName);
         assertEquals(TestConstants.TOS_URL, flowParameters.termsOfServiceUrl);
         assertEquals(TestConstants.PRIVACY_URL, flowParameters.privacyPolicyUrl);
@@ -93,6 +94,12 @@ public void testCreatingStartIntent_withNullPp_expectEnforcesNonNullPpUrl() {
         startIntent.setTosAndPrivacyPolicyUrls(TestConstants.TOS_URL, null);
     }
 
+    @Test(expected = IllegalStateException.class)
+    public void testCreatingStartIntent_withOnlyAnonymousProvider_expectIllegalStateException() {
+        SignInIntentBuilder startIntent = mAuthUi.createSignInIntentBuilder();
+        startIntent.setAvailableProviders(Arrays.asList(new IdpConfig.AnonymousBuilder().build()));
+    }
+
     @Test(expected = IllegalArgumentException.class)
     public void testPhoneBuilder_withBlacklistedDefaultNumberCode_expectIllegalArgumentException() {
         new IdpConfig.PhoneBuilder()
@@ -202,4 +209,11 @@ public void testPhoneBuilder_passNullForBlacklistedCountries_expectNullPointerEx
                 .setBlacklistedCountries(null)
                 .build();
     }
+
+    @Test
+    public void testAnonymousBuilder_expectSucess() {
+        new IdpConfig.AnonymousBuilder()
+                .build();
+    }
+
 }
diff --git a/auth/src/test/java/com/firebase/ui/auth/testhelpers/TestHelper.java b/auth/src/test/java/com/firebase/ui/auth/testhelpers/TestHelper.java
index 45a79924f..6ca3d5fa5 100644
--- a/auth/src/test/java/com/firebase/ui/auth/testhelpers/TestHelper.java
+++ b/auth/src/test/java/com/firebase/ui/auth/testhelpers/TestHelper.java
@@ -126,6 +126,9 @@ public static FlowParameters getFlowParameters(Collection<String> providerIds,
                 case PhoneAuthProvider.PROVIDER_ID:
                     idpConfigs.add(new IdpConfig.PhoneBuilder().build());
                     break;
+                case AuthUI.ANONYMOUS_PROVIDER:
+                    idpConfigs.add(new IdpConfig.AnonymousBuilder().build());
+                    break;
                 default:
                     throw new IllegalArgumentException("Unknown provider: " + providerId);
             }
diff --git a/auth/src/test/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivityTest.java b/auth/src/test/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivityTest.java
index 50b8ccc9b..9da3b2a73 100644
--- a/auth/src/test/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivityTest.java
+++ b/auth/src/test/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivityTest.java
@@ -18,6 +18,7 @@
 import android.widget.Button;
 import android.widget.LinearLayout;
 
+import com.firebase.ui.auth.AuthUI;
 import com.firebase.ui.auth.R;
 import com.firebase.ui.auth.testhelpers.TestHelper;
 import com.firebase.ui.auth.ui.email.EmailActivity;
@@ -56,13 +57,14 @@ public void testAllProvidersArePopulated() {
                 GoogleAuthProvider.PROVIDER_ID,
                 TwitterAuthProvider.PROVIDER_ID,
                 EmailAuthProvider.PROVIDER_ID,
-                PhoneAuthProvider.PROVIDER_ID);
+                PhoneAuthProvider.PROVIDER_ID,
+                AuthUI.ANONYMOUS_PROVIDER);
 
         AuthMethodPickerActivity authMethodPickerActivity = createActivity(providers);
 
         assertEquals(providers.size(),
-                     ((LinearLayout) authMethodPickerActivity.findViewById(R.id.btn_holder))
-                             .getChildCount());
+                ((LinearLayout) authMethodPickerActivity.findViewById(R.id.btn_holder))
+                        .getChildCount());
     }
 
     @Test
diff --git a/auth/src/test/java/com/firebase/ui/auth/viewmodel/AnonymousSignInHandlerTest.java b/auth/src/test/java/com/firebase/ui/auth/viewmodel/AnonymousSignInHandlerTest.java
new file mode 100644
index 000000000..57d6696b3
--- /dev/null
+++ b/auth/src/test/java/com/firebase/ui/auth/viewmodel/AnonymousSignInHandlerTest.java
@@ -0,0 +1,98 @@
+package com.firebase.ui.auth.viewmodel;
+
+import android.arch.lifecycle.Observer;
+
+import com.firebase.ui.auth.IdpResponse;
+import com.firebase.ui.auth.data.model.FlowParameters;
+import com.firebase.ui.auth.data.model.Resource;
+import com.firebase.ui.auth.data.model.State;
+import com.firebase.ui.auth.data.remote.AnonymousSignInHandler;
+import com.firebase.ui.auth.testhelpers.AutoCompleteTask;
+import com.firebase.ui.auth.testhelpers.FakeAuthResult;
+import com.firebase.ui.auth.testhelpers.ResourceMatchers;
+import com.firebase.ui.auth.testhelpers.TestHelper;
+import com.google.firebase.auth.AuthResult;
+import com.google.firebase.auth.FirebaseAuth;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+import java.util.ArrayList;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.ArgumentMatchers.argThat;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+/**
+ * Unit tests for {@link AnonymousSignInHandler}.
+ */
+@RunWith(RobolectricTestRunner.class)
+public class AnonymousSignInHandlerTest {
+
+    @Mock FirebaseAuth mMockAuth;
+    AnonymousSignInHandler mHandler;
+
+    @Mock Observer<Resource<IdpResponse>> mResponseObserver;
+
+    @Before
+    public void setUp() {
+        TestHelper.initialize();
+        MockitoAnnotations.initMocks(this);
+
+        mHandler = new AnonymousSignInHandler(RuntimeEnvironment.application);
+        FlowParameters testParams = TestHelper.getFlowParameters(new ArrayList<String>());
+        mHandler.init(testParams);
+        mHandler.mAuth = mMockAuth;
+    }
+
+    @Test
+    public void testStartSignIn_expectSuccess() {
+        mHandler.getOperation().observeForever(mResponseObserver);
+
+        when(mMockAuth.signInAnonymously())
+                .thenReturn(AutoCompleteTask.forSuccess(FakeAuthResult.INSTANCE));
+
+        mHandler.startSignIn(null);
+
+        verify(mMockAuth).signInAnonymously();
+
+        InOrder inOrder = inOrder(mResponseObserver);
+        inOrder.verify(mResponseObserver)
+                .onChanged(argThat(ResourceMatchers.<IdpResponse>isLoading()));
+
+        ArgumentCaptor<Resource<IdpResponse>> captor = ArgumentCaptor.forClass(Resource.class);
+        inOrder.verify(mResponseObserver).onChanged(captor.capture());
+
+        assertThat(captor.getValue().getState()).isEqualTo(State.SUCCESS);
+        IdpResponse response = captor.getValue().getValue();
+        assertThat(response.isNewUser()).isFalse();
+    }
+
+    @Test
+    public void testStartSignIn_expectFailure() {
+        mHandler.getOperation().observeForever(mResponseObserver);
+
+        when(mMockAuth.signInAnonymously())
+                .thenReturn(AutoCompleteTask.<AuthResult>forFailure(new Exception("FAILED")));
+
+        mHandler.startSignIn(null);
+
+        verify(mMockAuth).signInAnonymously();
+
+        InOrder inOrder = inOrder(mResponseObserver);
+        inOrder.verify(mResponseObserver)
+                .onChanged(argThat(ResourceMatchers.<IdpResponse>isLoading()));
+        inOrder.verify(mResponseObserver)
+                .onChanged(argThat(ResourceMatchers.<IdpResponse>isFailure()));
+
+    }
+}
diff --git a/auth/src/test/java/com/firebase/ui/auth/viewmodel/LinkingSocialProviderResponseHandlerTest.java b/auth/src/test/java/com/firebase/ui/auth/viewmodel/LinkingSocialProviderResponseHandlerTest.java
index 068f9c38a..d8686a2a2 100644
--- a/auth/src/test/java/com/firebase/ui/auth/viewmodel/LinkingSocialProviderResponseHandlerTest.java
+++ b/auth/src/test/java/com/firebase/ui/auth/viewmodel/LinkingSocialProviderResponseHandlerTest.java
@@ -22,7 +22,6 @@
 import com.google.firebase.auth.FirebaseUser;
 import com.google.firebase.auth.GoogleAuthCredential;
 import com.google.firebase.auth.GoogleAuthProvider;
-import com.google.firebase.auth.PhoneAuthCredential;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -59,7 +58,6 @@ public class LinkingSocialProviderResponseHandlerTest {
     @Mock FirebaseAuth mScratchMockAuth;
 
     @Mock FirebaseUser mMockUser;
-    @Mock PhoneAuthCredential mCredential;
     @Mock Observer<Resource<IdpResponse>> mResponseObserver;
 
     private LinkingSocialProviderResponseHandler mHandler;
diff --git a/library/quality/lint-baseline.xml b/library/quality/lint-baseline.xml
index 3e6a355dd..3217e43a5 100644
--- a/library/quality/lint-baseline.xml
+++ b/library/quality/lint-baseline.xml
@@ -7,5 +7,4 @@
         message="The project references RTL attributes, but does not explicitly enable or disable RTL support with `android:supportsRtl` in the manifest">
         <location file="src/main/AndroidManifest.xml" />
     </issue>
-
 </issues>