only mock timer functions currently mocked by Jest

docs/JestObjectAPI.md

@@ -460,14 +460,6 @@ This means, if any timers have been scheduled (but have not yet executed), they
 
 Returns the number of fake timers still left to run.
 
-### `.jest.setSystemTime()`
-
-Set the current system time used by fake timers. Simulates a user changing the system clock while your program is running. It affects the current time but it does not in itself cause e.g. timers to fire; they will fire exactly as they would have done without the call to `jest.setSystemTime()`.
-
-### `.jest.getRealSystemTime()`
-
-When mocking time, `Date.now()` will also be mocked. If you for some reason need access to the real current time, you can invoke this function.
-
 ## Misc
 
 ### `jest.setTimeout(timeout)`

flow-typed/npm/lolex_v2.x.x.js

@@ -40,7 +40,6 @@ declare module 'lolex' {
     runMicrotasks(): void;
     runToFrame(): void;
     runToLast(): void;
-    setSystemTime(now?: number | Date): void;
     uninstall(): Object[];
     Date: typeof Date;
     Performance: typeof Performance;

packages/jest-runtime/src/index.js

@@ -1002,7 +1002,6 @@ class Runtime {
       fn,
       genMockFromModule: (moduleName: string) =>
         this._generateMock(from, moduleName),
-      getRealSystemTime: () => _getFakeTimers().getRealSystemTime(),
       getTimerCount: () => _getFakeTimers().getTimerCount(),
       isMockFunction: this._moduleMocker.isMockFunction,
       isolateModules,
@@ -1021,7 +1020,6 @@ class Runtime {
         _getFakeTimers().advanceTimersByTime(msToRun),
       setMock: (moduleName: string, mock: Object) =>
         setMockFactory(moduleName, () => mock),
-      setSystemTime: (now?: number) => _getFakeTimers().setSystemTime(now),
       setTimeout,
       spyOn,
       unmock,

packages/jest-util/src/FakeTimers.js

@@ -81,14 +81,20 @@ export default class FakeTimers {
   }
 
   useFakeTimers() {
-    const toFake = Object.keys(this._lolex.timers);
-
     if (!this._fakingTime) {
       this._clock = this._lolex.install({
         loopLimit: this._maxLoops,
         now: Date.now(),
         target: this._global,
-        toFake,
+        toFake: [
+          'setTimeout',
+          'clearTimeout',
+          'setImmediate',
+          'clearImmediate',
+          'setInterval',
+          'clearInterval',
+          'nextTick',
+        ],
       });
 
       this._fakingTime = true;
@@ -97,22 +103,10 @@ export default class FakeTimers {
 
   reset() {
     if (this._checkFakeTimers()) {
-      const {now} = this._clock;
       this._clock.reset();
-      this._clock.setSystemTime(now);
     }
   }
 
-  setSystemTime(now?: number) {
-    if (this._checkFakeTimers()) {
-      this._clock.setSystemTime(now);
-    }
-  }
-
-  getRealSystemTime() {
-    return Date.now();
-  }
-
   getTimerCount() {
     if (this._checkFakeTimers()) {
       return this._clock.countTimers();

types/Environment.js

@@ -29,8 +29,6 @@ declare class $JestEnvironment {
     runOnlyPendingTimers(): void,
     runWithRealTimers(callback: any): void,
     getTimerCount(): number,
-    setSystemTime(now?: number): void,
-    getRealSystemTime(): number,
     useFakeTimers(): void,
     useRealTimers(): void,
   };

types/Jest.js

@@ -36,8 +36,6 @@ export type Jest = {|
   runAllTicks(): void,
   runAllTimers(): void,
   runOnlyPendingTimers(): void,
-  getRealSystemTime(): number,
-  setSystemTime(now?: number): void,
   advanceTimersByTime(msToRun: number): void,
   runTimersToTime(msToRun: number): void,
   getTimerCount(): number,