Add Firebase auth emulator

pom.xml

@@ -352,7 +352,7 @@
                             <goal>integration-test</goal>
                             <goal>verify</goal>
                         </goals>
-                    </execution>                    
+                    </execution>
                 </executions>
             </plugin>
 
@@ -490,5 +490,12 @@
             <version>2.0</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <!-- Used for change env system -->
+            <groupId>com.github.stefanbirkner</groupId>
+            <artifactId>system-rules</artifactId>
+            <version>1.19.0</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>

src/main/java/com/google/firebase/auth/FirebaseUserManager.java

@@ -72,6 +72,8 @@ final class FirebaseUserManager {
 
   private static final String ID_TOOLKIT_URL =
       "https://identitytoolkit.googleapis.com/%s/projects/%s";
+  private static final String ID_TOOLKIT_URL_EMULATOR =
+          "http://%s/identitytoolkit.googleapis.com/%s/projects/%s";
 
   private final String userMgtBaseUrl;
   private final String idpConfigMgtBaseUrl;
@@ -85,8 +87,8 @@ private FirebaseUserManager(Builder builder) {
             + "set the project ID explicitly via FirebaseOptions. Alternatively you can also "
             + "set the project ID via the GOOGLE_CLOUD_PROJECT environment variable.");
     this.jsonFactory = checkNotNull(builder.jsonFactory, "JsonFactory must not be null");
-    final String idToolkitUrlV1 = String.format(ID_TOOLKIT_URL, "v1", projectId);
-    final String idToolkitUrlV2 = String.format(ID_TOOLKIT_URL, "v2", projectId);
+    final String idToolkitUrlV1 = getIdToolkitUrl(projectId, "v1");
+    final String idToolkitUrlV2 = getIdToolkitUrl(projectId, "v2");
     final String tenantId = builder.tenantId;
     if (tenantId == null) {
       this.userMgtBaseUrl = idToolkitUrlV1;
@@ -100,6 +102,18 @@ private FirebaseUserManager(Builder builder) {
     this.httpClient = new AuthHttpClient(jsonFactory, builder.requestFactory);
   }
 
+  private String getIdToolkitUrl(String projectId, String version) {
+    String maybeEmulator = getEmulatorHost();
+    if (maybeEmulator != null) {
+      return String.format(ID_TOOLKIT_URL_EMULATOR, maybeEmulator, version, projectId);
+    }
+    return String.format(ID_TOOLKIT_URL, version, projectId);
+  }
+
+  private String getEmulatorHost() {
+    return System.getenv("FIREBASE_AUTH_EMULATOR_HOST");
+  }
+
   @VisibleForTesting
   void setInterceptor(HttpResponseInterceptor interceptor) {
     httpClient.setInterceptor(interceptor);

src/main/java/com/google/firebase/auth/multitenancy/FirebaseTenantClient.java

@@ -42,6 +42,9 @@ final class FirebaseTenantClient {
   private static final String ID_TOOLKIT_URL =
       "https://identitytoolkit.googleapis.com/%s/projects/%s";
 
+  private static final String ID_TOOLKIT_URL_EMULATOR =
+          "http://%s/identitytoolkit.googleapis.com/%s/projects/%s";
+
   private final String tenantMgtBaseUrl;
   private final AuthHttpClient httpClient;
 
@@ -58,10 +61,22 @@ final class FirebaseTenantClient {
         "Project ID is required to access the auth service. Use a service account credential or "
             + "set the project ID explicitly via FirebaseOptions. Alternatively you can also "
             + "set the project ID via the GOOGLE_CLOUD_PROJECT environment variable.");
-    this.tenantMgtBaseUrl = String.format(ID_TOOLKIT_URL, "v2", projectId);
+    this.tenantMgtBaseUrl = getTenantMgtBaseUrl(projectId);
     this.httpClient = new AuthHttpClient(jsonFactory, requestFactory);
   }
 
+  private String getTenantMgtBaseUrl(String projectId) {
+    String maybeEmulator = getEmulatorHost();
+    if (maybeEmulator != null) {
+      return String.format(ID_TOOLKIT_URL_EMULATOR, maybeEmulator, "v2", projectId);
+    }
+    return String.format(ID_TOOLKIT_URL, "v2", projectId);
+  }
+
+  private String getEmulatorHost() {
+    return System.getenv("FIREBASE_AUTH_EMULATOR_HOST");
+  }
+
   void setInterceptor(HttpResponseInterceptor interceptor) {
     httpClient.setInterceptor(interceptor);
   }

src/test/java/com/google/firebase/auth/FirebaseUserManagerTest.java

@@ -62,7 +62,9 @@
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import org.junit.After;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.contrib.java.lang.system.EnvironmentVariables;
 
 public class FirebaseUserManagerTest {
 
@@ -90,12 +92,20 @@ public class FirebaseUserManagerTest {
 
   private static final String TENANTS_BASE_URL = PROJECT_BASE_URL + "/tenants";
 
+  private static final String AUTH_EMULATOR = "localhost:8000";
+  private static final String PROJECT_BASE_URL_EMULATOR =
+          "http://" + AUTH_EMULATOR + "/identitytoolkit.googleapis.com/v2/projects/test-project-id";
+
   private static final String SAML_RESPONSE = TestUtils.loadResource("saml.json");
 
   private static final String OIDC_RESPONSE = TestUtils.loadResource("oidc.json");
 
+  @Rule
+  public final EnvironmentVariables environmentVariables = new EnvironmentVariables();
+
   @After
   public void tearDown() {
+    environmentVariables.clear("FIREBASE_AUTH_EMULATOR_HOST", AUTH_EMULATOR);
     TestOnlyImplFirebaseTrampolines.clearInstancesForTest();
   }
 
@@ -1517,7 +1527,7 @@ public void testCreateOidcProviderAsync() throws Exception {
             .setClientId("CLIENT_ID")
             .setIssuer("https://oidc.com/issuer");
 
-    OidcProviderConfig config = 
+    OidcProviderConfig config =
         FirebaseAuth.getInstance().createOidcProviderConfigAsync(createRequest).get();
 
     checkOidcProviderConfig(config, "oidc.provider-id");
@@ -2678,6 +2688,32 @@ public void testTenantAwareDeleteSamlProviderConfig() throws Exception {
     checkUrl(interceptor, "DELETE", expectedUrl);
   }
 
+  @Test
+  public void testCreateOidcProviderFromEmulatorAuth() throws Exception {
+    environmentVariables.set("FIREBASE_AUTH_EMULATOR_HOST", AUTH_EMULATOR);
+    TestResponseInterceptor interceptor = initializeAppForUserManagement(OIDC_RESPONSE);
+    OidcProviderConfig.CreateRequest createRequest =
+            new OidcProviderConfig.CreateRequest()
+                    .setProviderId("oidc.provider-id")
+                    .setDisplayName("DISPLAY_NAME")
+                    .setEnabled(true)
+                    .setClientId("CLIENT_ID")
+                    .setIssuer("https://oidc.com/issuer");
+
+    OidcProviderConfig config = FirebaseAuth.getInstance().createOidcProviderConfig(createRequest);
+
+    checkOidcProviderConfig(config, "oidc.provider-id");
+    checkRequestHeaders(interceptor);
+    checkUrl(interceptor, "POST", PROJECT_BASE_URL_EMULATOR + "/oauthIdpConfigs");
+    GenericJson parsed = parseRequestContent(interceptor);
+    assertEquals("DISPLAY_NAME", parsed.get("displayName"));
+    assertTrue((boolean) parsed.get("enabled"));
+    assertEquals("CLIENT_ID", parsed.get("clientId"));
+    assertEquals("https://oidc.com/issuer", parsed.get("issuer"));
+    GenericUrl url = interceptor.getResponse().getRequest().getUrl();
+    assertEquals("oidc.provider-id", url.getFirst("oauthIdpConfigId"));
+  }
+
   private static TestResponseInterceptor initializeAppForUserManagementWithStatusCode(
       int statusCode, String response) {
     FirebaseApp.initializeApp(FirebaseOptions.builder()

src/test/java/com/google/firebase/auth/multitenancy/FirebaseTenantClientTest.java

@@ -52,8 +52,11 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+
 import org.junit.After;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.contrib.java.lang.system.EnvironmentVariables;
 
 public class FirebaseTenantClientTest {
 
@@ -68,8 +71,17 @@ public class FirebaseTenantClientTest {
 
   private static final String TENANTS_BASE_URL = PROJECT_BASE_URL + "/tenants";
 
+  private static final String AUTH_EMULATOR = "localhost:8000";
+  private static final String PROJECT_BASE_URL_EMULATOR =
+          "http://" + AUTH_EMULATOR + "/identitytoolkit.googleapis.com/v2/projects/test-project-id";
+  private static final String TENANTS_BASE_URL_EMULATOR = PROJECT_BASE_URL_EMULATOR + "/tenants";
+
+  @Rule
+  public final EnvironmentVariables environmentVariables = new EnvironmentVariables();
+
   @After
-  public void tearDown() {
+  public void tearDown() throws ReflectiveOperationException {
+    environmentVariables.clear("FIREBASE_AUTH_EMULATOR_HOST", AUTH_EMULATOR);
     TestOnlyImplFirebaseTrampolines.clearInstancesForTest();
   }
 
@@ -312,6 +324,19 @@ public void testDeleteTenantWithNotFoundError() {
     checkUrl(interceptor, "DELETE", TENANTS_BASE_URL + "/UNKNOWN");
   }
 
+  @Test
+  public void testGetTenantFromAuthEmulator() throws Exception {
+    environmentVariables.set("FIREBASE_AUTH_EMULATOR_HOST", AUTH_EMULATOR);
+    TestResponseInterceptor interceptor = initializeAppForTenantManagement(
+            TestUtils.loadResource("tenant.json"));
+
+    Tenant tenant = FirebaseAuth.getInstance().getTenantManager().getTenant("TENANT_1");
+
+    checkTenant(tenant, "TENANT_1");
+    checkRequestHeaders(interceptor);
+    checkUrl(interceptor, "GET", TENANTS_BASE_URL_EMULATOR + "/TENANT_1");
+  }
+
   private static void checkTenant(Tenant tenant, String tenantId) {
     assertEquals(tenantId, tenant.getTenantId());
     assertEquals("DISPLAY_NAME", tenant.getDisplayName());