From b641de08eaa0aa2ff4ca691e9f9f2801b4544837 Mon Sep 17 00:00:00 2001
From: Silvio Ginter <silvio.ginter@googlemail.com>
Date: Wed, 23 Aug 2017 16:33:19 +0200
Subject: [PATCH] [@types/jest] Fix tsc rejects constructor arguments for
 Mock<T>, as it works like intended (#19268)

* Fix tsc rejects constructor arguments for Mock<T>, as it works like intended

* apply code format
---
 types/jest/index.d.ts    |  2 +-
 types/jest/jest-tests.ts | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/types/jest/index.d.ts b/types/jest/index.d.ts
index 396e9a0de0..3c9eb27d93 100644
--- a/types/jest/index.d.ts
+++ b/types/jest/index.d.ts
@@ -475,7 +475,7 @@ declare namespace jest {
     }
 
     interface Mock<T> extends Function, MockInstance<T> {
-        new (): T;
+        new (...args: any[]): T;
         (...args: any[]): any;
     }
 
diff --git a/types/jest/jest-tests.ts b/types/jest/jest-tests.ts
index 7e5ed2567f..ff01b154ad 100644
--- a/types/jest/jest-tests.ts
+++ b/types/jest/jest-tests.ts
@@ -539,6 +539,36 @@ describe('Mocks', () => {
         const anotherIns: jest.Mocked<TestApi> = new anotherMock() as any;
         anotherIns.testMethod.mockImplementation(() => 1);
     });
+
+    it('jest.fn() accepts constructor arguments', () => {
+        interface TestLog {
+            log(...msg: any[]): void;
+        }
+
+        class LogMock extends jest.fn<TestLog>((verbose?: boolean) => {
+            const mockLog = () => {
+                if (verbose) {
+                    return jest.fn((...args) => {
+                        const subj = args.shift() || "";
+                        console.log(subj, ...args);
+                    });
+                }
+                return jest.fn();
+            };
+
+            return {
+                log: mockLog()
+            };
+        }) {
+        }
+
+        const nonVerboseLog = new LogMock();
+        nonVerboseLog.log("this is completely catched by jest");
+        expect(nonVerboseLog.log).toBeCalledWith("this is completely catched by jest");
+        const verboseLog = new LogMock(true);
+        verboseLog.log("this should also be printed to the console");
+        expect(verboseLog.log).toBeCalledWith("this should also be printed to the console");
+    });
 });
 
 // https://facebook.github.io/jest/docs/en/expect.html#resolves