improves test performance on mongodb (#4862)

* improves test performance on mongodb

* Removes unused methdos

src/Adapters/Storage/Mongo/MongoStorageAdapter.js

@@ -313,11 +313,9 @@ export class MongoStorageAdapter implements StorageAdapter {
       .catch(err => this.handleError(err));
   }
 
-  // Delete all data known to this adapter. Used for testing.
-  deleteAllClasses() {
-    return storageAdapterAllCollections(this)
-      .then(collections => Promise.all(collections.map(collection => collection.drop())))
-      .catch(err => this.handleError(err));
+  dropDatabase() {
+    if (!this.database) { return Promise.resolve(); }
+    return this.database.dropDatabase();
   }
 
   // Remove the column and all the data. For Relations, the _Join collection is handled

src/Adapters/Storage/Postgres/PostgresStorageAdapter.js

@@ -959,6 +959,10 @@ export class PostgresStorageAdapter implements StorageAdapter {
       });
   }
 
+  dropDatabase() {
+    return this.deleteAllClasses();
+  }
+
   // Remove the column and all the data. For Relations, the _Join collection is handled
   // specially, this function does not delete _Join columns. It should, however, indicate
   // that the relation fields does not exist anymore. In mongo, this means removing it from

src/Adapters/Storage/StorageAdapter.js

@@ -32,6 +32,7 @@ export interface StorageAdapter {
   addFieldIfNotExists(className: string, fieldName: string, type: any): Promise<void>;
   deleteClass(className: string): Promise<void>;
   deleteAllClasses(): Promise<void>;
+  dropDatabase(): Promise<void>;
   deleteFields(className: string, schema: SchemaType, fieldNames: Array<string>): Promise<void>;
   getAllClasses(): Promise<StorageClass[]>;
   getClass(className: string): Promise<StorageClass>;

src/Controllers/DatabaseController.js

@@ -658,7 +658,7 @@ class DatabaseController {
   deleteEverything() {
     this.schemaPromise = null;
     return Promise.all([
-      this.adapter.deleteAllClasses(),
+      this.adapter.dropDatabase(),
       this.schemaCache.clear()
     ]);
   }