From b6518e933bb41fb9e0dcb81894351a21935a1cce Mon Sep 17 00:00:00 2001
From: Rohan <rohan@MobileAppDev.nova.co.nz>
Date: Thu, 28 Jun 2018 11:09:01 +1200
Subject: [PATCH] support mocking native async methods when targeting es2017

---
 package.json                                  |  7 ++-
 src/utils/MockableFunctionsFinder.ts          |  3 +-
 test/mocking.types.spec.ts                    | 61 +++++++++++++++++++
 test/utils/MockableFunctionsFinder.spec.ts    |  9 +++
 .../utils/ObjectPropertyCodeRetriever.spec.ts |  2 +-
 tsconfig.test.json                            |  9 +++
 6 files changed, 88 insertions(+), 3 deletions(-)
 create mode 100644 tsconfig.test.json

diff --git a/package.json b/package.json
index b6674d6..c9fdf2c 100644
--- a/package.json
+++ b/package.json
@@ -56,9 +56,14 @@
     "lodash": "^4.17.5"
   },
   "jest": {
+    "globals": {
+      "ts-jest": {
+        "tsConfigFile": "tsconfig.test.json"
+      }
+    },
     "testEnvironment": "jsdom",
     "transform": {
-      "^.+\\.ts$": "<rootDir>/node_modules/ts-jest/preprocessor.js"
+      "^.+\\.ts$": "ts-jest"
     },
     "testRegex": "(/__tests__/.*|\\.(spec))\\.(ts|js)$",
     "moduleFileExtensions": [
diff --git a/src/utils/MockableFunctionsFinder.ts b/src/utils/MockableFunctionsFinder.ts
index 600b1cd..a7bef46 100644
--- a/src/utils/MockableFunctionsFinder.ts
+++ b/src/utils/MockableFunctionsFinder.ts
@@ -7,9 +7,10 @@
  *     - [.]functionName = (
  *     - [.]functionName = function(
  *     - [.]functionName = function otherName(
+ *     - [.]functionName = async .
  */
 export class MockableFunctionsFinder {
-    private functionNameRegex = /[.\s]([^.\s]+?)(?:\(|\s+=\s+(?:function\s*(?:[^.\s]+?\s*)?)?\()/g;
+    private functionNameRegex = /[.\s]([^.\s]+?)(?:\(|\s+=\s+(?:function\s*(?:[^.\s]+?\s*)?)?\(|\s+=\s+async\s)/g;
     private cleanFunctionNameRegex = /^[.\s]([^.\s]+?)[\s(]/;
     private excludedFunctionNames: string[] = ["hasOwnProperty", "function"];
 
diff --git a/test/mocking.types.spec.ts b/test/mocking.types.spec.ts
index cfd86df..8173289 100644
--- a/test/mocking.types.spec.ts
+++ b/test/mocking.types.spec.ts
@@ -152,6 +152,57 @@ describe("mocking", () => {
 
         });
     });
+
+    describe("mocking class with async methods", () => {
+      let mockedFoo: SampleClassWithAsync;
+      let foo: SampleClassWithAsync;
+
+      it("does create own method descriptors on instance 0", () => {
+        // given
+        mockedFoo = mock(SampleClassWithAsync);
+        foo = instance(mockedFoo);
+
+        // when
+        when(mockedFoo.asyncMethod0()).thenResolve(42);
+
+        // then
+        return foo.asyncMethod0()
+          .then(result => {
+            expect(result).toBe(42);
+          });
+      });
+
+      it("does create own method descriptors on instance 1", () => {
+        // given
+        mockedFoo = mock(SampleClassWithAsync);
+        foo = instance(mockedFoo);
+
+        // when
+        when(mockedFoo.asyncMethod1('bar')).thenResolve(42);
+
+        // then
+        return foo.asyncMethod1('bar')
+          .then(result => {
+            expect(result).toBe(42);
+          });
+      });
+
+      it("does create own method descriptors on instance 2", () => {
+        // given
+        mockedFoo = mock(SampleClassWithAsync);
+        foo = instance(mockedFoo);
+
+        // when
+        when(mockedFoo.asyncMethod2('bar', 2)).thenResolve(42);
+
+        // then
+        return foo.asyncMethod2('bar', 2)
+          .then(result => {
+            expect(result).toBe(42);
+          });
+      });
+});
+
 });
 
 abstract class SampleAbstractClass {
@@ -211,3 +262,13 @@ class SampleGeneric<T> {
         return null;
     }
 }
+
+class SampleClassWithAsync {
+
+  protected constructor() {}
+
+  // because the compiler produces different signatures for each of these
+  public asyncMethod0 = async () => 4;
+  public asyncMethod1 = async (foo: string) => Number(foo);
+  public asyncMethod2 = async (foo: string, bar: number) => bar;
+}
diff --git a/test/utils/MockableFunctionsFinder.spec.ts b/test/utils/MockableFunctionsFinder.spec.ts
index 894d0f7..c8e2089 100644
--- a/test/utils/MockableFunctionsFinder.spec.ts
+++ b/test/utils/MockableFunctionsFinder.spec.ts
@@ -13,6 +13,8 @@ describe("MockableFunctionsFinder", () => {
             expect(result).toContain("log");
             expect(result).toContain("toString");
             expect(result).toContain("anonymousMethod");
+            expect(result).toContain("asyncMethod1");
+            expect(result).toContain("asyncMethod2");
         });
 
         it("should not find hasOwnProperty as it should not be mocked (because its used by mockito to evaluate properties)", () => {
@@ -36,6 +38,13 @@ export class Foo {
             console.log(arg);
             temp.hasOwnProperty("fakeProperty");
         }
+
+        this.asyncMethod1 = async arg => {
+        }
+
+        this.asyncMethod2 = async (foo, bar) => {
+        }
+
     }
 
     private convertNumberToString(value:number):string {
diff --git a/test/utils/ObjectPropertyCodeRetriever.spec.ts b/test/utils/ObjectPropertyCodeRetriever.spec.ts
index 139c23c..b3c5f58 100644
--- a/test/utils/ObjectPropertyCodeRetriever.spec.ts
+++ b/test/utils/ObjectPropertyCodeRetriever.spec.ts
@@ -28,7 +28,7 @@ describe("ObjectPropertyCodeRetriever", () => {
             expect(objectPropertyCodeRetriever.get(object, "nanProperty")).toBe("NaN");
             expect(objectPropertyCodeRetriever.get(object, "stringProperty")).toBe("stringProperty");
             expect(objectPropertyCodeRetriever.get(object, "booleanProperty")).toBe("true");
-            expect(objectPropertyCodeRetriever.get(object, "testMethod")).toMatch(/function \(\)/);
+            expect(objectPropertyCodeRetriever.get(object, "testMethod")).toMatch(/() => true/);
         });
 
         it("Provides code of given existing property accessors", () => {
diff --git a/tsconfig.test.json b/tsconfig.test.json
new file mode 100644
index 0000000..12b3ac4
--- /dev/null
+++ b/tsconfig.test.json
@@ -0,0 +1,9 @@
+{
+  "extends": "./tsconfig",
+  "compilerOptions": {
+    "target": "es2017",
+    "lib": [
+      "es2017"
+    ]
+  }
+}