added tests to cover promises.

Author: Mathias Lorenzen

dist/spec/index.test.d.ts

@@ -4,5 +4,6 @@ export declare class Example {
     readonly d: number;
     v: string;
     received(stuff: number | string): void;
+    returnPromise(): Promise<number>;
     foo(): string;
 }

dist/spec/index.test.js

@@ -23,6 +23,10 @@ export class Example {
 
 	}
 
+	returnPromise() {
+		return Promise.resolve(1337);
+	}
+
 	foo() {
 		return 'stuff';
 	}
@@ -40,6 +44,12 @@ test.beforeEach(() => {
 	substitute = Substitute.for<Example>();
 });
 
+test('returning resolved promises works', async t => {
+	substitute.returnPromise().returns(Promise.resolve(1338));
+
+	t.is(1338, await substitute.returnPromise());
+});
+
 test('class string field set received', t => {
 	substitute.v = undefined;
 	substitute.v = null;