test(firestore): allow firestore database override

tests/FirebaseProjectManagerTest.php

@@ -276,6 +276,34 @@ public function it_uses_the_laravel_cache_as_verifier_cache(): void
         $this->assertInstanceOf(CacheItemPoolInterface::class, $property->getValue($factory));
     }
 
+    /**
+     * @test
+     */
+    public function it_use_the_default_firestore_database(): void
+    {
+        config(['firebase.projects.app.firestore.database' => null]);
+        $projectName = $this->app->config->get('firebase.default');
+        $factory = $this->factoryForProject($projectName);
+
+        $property = $this->getAccessibleProperty($factory, 'firestoreClientConfig');
+
+        $this->assertEquals('(default)', $property->getValue($factory)['database']);
+    }
+
+    /**
+     * @test
+     */
+    public function it_overrides_the_default_firestore_database(): void
+    {
+        config(['firebase.projects.app.firestore.database' => 'override-database']);
+        $projectName = $this->app->config->get('firebase.default');
+        $factory = $this->factoryForProject($projectName);
+
+        $property = $this->getAccessibleProperty($factory, 'firestoreClientConfig');
+
+        $this->assertEquals('override-database', $property->getValue($factory)['database']);
+    }
+
     /**
      * @test
      */
@@ -289,7 +317,7 @@ public function it_uses_the_laravel_cache_as_auth_token_cache(): void
         $this->assertInstanceOf(CacheItemPoolInterface::class, $property->getValue($factory));
     }
 
-    private function factoryForProject(string $project = null): Factory
+    private function factoryForProject(?string $project = null): Factory
     {
         $project = $this->app->make(FirebaseProjectManager::class)->project($project);