How can I get XCTest to wait for async calls in setUp before tests are run?

Question

I'm writing integration tests in Xcode 6 to go alongside my unit and functional tests. XCTest has a setUp() method that gets called before every test. Great!

It also has XCTestException's which let me write async tests. Also great!

However, I would like to populate my test database with test data before every test and setUp just starts executing tests before the async database call is done.

Is there a way to have setUp wait until my database is ready before it runs tests?

Here's an example of what I have do now. Since setUp returns before the database is done populating I have to duplicate a lot of test code every test:

func test_checkSomethingExists() {      let expectation = expectationWithDescription("")     var expected:DatabaseItem      // Fill out a database with data.      var data = getData()     overwriteDatabase(data, {       // Database populated.       // Do test... in this pseudocode I just check something...       db.retrieveDatabaseItem({ expected in          XCTAssertNotNil(expected)          expectation.fulfill()       })     })      waitForExpectationsWithTimeout(5.0) { (error) in         if error != nil {             XCTFail(error.localizedDescription)         }     }  } 

Here's what I would like:

class MyTestCase: XCTestCase {      override func setUp() {         super.setUp()          // Fill out a database with data. I can make this call do anything, here         // it returns a block.         var data = getData()         db.overwriteDatabase(data, onDone: () -> () {             // When database done, do something that causes setUp to end             // and start running tests          })             }      func test_checkSomethingExists() {          let expectation = expectationWithDescription("")         var expected:DatabaseItem             // Do test... in this pseudocode I just check something...           db.retrieveDatabaseItem({ expected in              XCTAssertNotNil(expected)              expectation.fulfill()         })          waitForExpectationsWithTimeout(5.0) { (error) in             if error != nil {                 XCTFail(error.localizedDescription)             }         }      }  } 

Answer 1

Rather than using semaphores or blocking loops, you can use the same waitForExpectationsWithTimeout:handler: function you use in your async test cases.

// Swift override func setUp() {     super.setUp()      let exp = expectation(description: "\(#function)\(#line)")      // Issue an async request     let data = getData()     db.overwriteDatabase(data) {         // do some stuff         exp.fulfill()     }      // Wait for the async request to complete     waitForExpectations(timeout: 40, handler: nil) }  // Objective-C - (void)setUp {     [super setUp];      NSString *description = [NSString stringWithFormat:@"%s%d", __FUNCTION__, __LINE__];     XCTestExpectation *exp = [self expectationWithDescription:description];      // Issue an async request     NSData *data = [self getData];     [db overwriteDatabaseData: data block: ^(){         [exp fulfill];     }];              // Wait for the async request to complete     [self waitForExpectationsWithTimeout:40 handler: nil]; }