diff --git a/etc/api/angular_devkit/schematics/testing/index.d.ts b/etc/api/angular_devkit/schematics/testing/index.d.ts
index b2fd06c700a4..14148f616992 100644
--- a/etc/api/angular_devkit/schematics/testing/index.d.ts
+++ b/etc/api/angular_devkit/schematics/testing/index.d.ts
@@ -4,6 +4,7 @@ export declare class SchematicTestRunner {
     readonly tasks: TaskConfiguration[];
     constructor(_collectionName: string, collectionPath: string);
     callRule(rule: Rule, tree: Tree, parentContext?: Partial<SchematicContext>): Observable<Tree>;
+    registerCollection(collectionName: string, collectionPath: string): void;
     runExternalSchematic<SchematicSchemaT>(collectionName: string, schematicName: string, opts?: SchematicSchemaT, tree?: Tree): UnitTestTree;
     runExternalSchematicAsync<SchematicSchemaT>(collectionName: string, schematicName: string, opts?: SchematicSchemaT, tree?: Tree): Observable<UnitTestTree>;
     runSchematic<SchematicSchemaT>(schematicName: string, opts?: SchematicSchemaT, tree?: Tree): UnitTestTree;
diff --git a/packages/angular_devkit/schematics/testing/schematic-test-runner.ts b/packages/angular_devkit/schematics/testing/schematic-test-runner.ts
index 9b89f6f46057..02d12c4ff2ca 100644
--- a/packages/angular_devkit/schematics/testing/schematic-test-runner.ts
+++ b/packages/angular_devkit/schematics/testing/schematic-test-runner.ts
@@ -72,6 +72,10 @@ export class SchematicTestRunner {
   get logger(): logging.Logger { return this._logger; }
   get tasks(): TaskConfiguration[] { return [...this._engineHost.tasks]; }
 
+  registerCollection(collectionName: string, collectionPath: string) {
+    this._engineHost.registerCollection(collectionName, collectionPath);
+  }
+
   runSchematicAsync<SchematicSchemaT>(
     schematicName: string,
     opts?: SchematicSchemaT,