async
function
Wraps a test function in an asynchronous test zone. The test will automatically complete when all asynchronous calls within this zone are done. Can be used to wrap an inject call.
async(fn: Function): (done: any) => any
 Parameters
| fn | Type:  | 
Returns
(done: any) => any
Description
Example:
it('...', async(inject([AClass], (object) => {
  object.doSomething.then(() => {
    expect(...);
  })
});  
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Licensed under the Creative Commons Attribution License 4.0.
    https://v6.angular.io/api/core/testing/async