Hey guys. I am learning how to do testing.

I am having a little issue with that code. It throws a breakpoint at XCTAssertEqual() line (I've checked and I ma sure that no breakpoint was set by me). Test won't go any further no matter what I do, and testing will never end.

I have checked response's status code and existence of an error in seperate test. Follower is a Class that conforms to FollowerProtocol. (I am following some examples from Swift Testing book by Paul Hudson). Anyone happens to know what am I doing wrong here? Many thanks.

 func testFetchedFollowersFromGithubEqualTo1() {
        // Assert
        let sut         = URLSession(configuration: .default)
        let url         = URL(string: "https://api.github.com/users/jmgawecki/followers?per_page=1&page=1")

        let expectation = XCTestExpectation(description: "Completion handler invoked")

        var followers:  [Follower] = []
        let decoder     = JSONDecoder()

        // Act
        let dataTask    = sut.dataTask(with: url!) { (data, response, error) in
            guard let data = data else { return }

            do {
                decoder.keyDecodingStrategy = .convertFromSnakeCase
                followers                   = try decoder.decode([Follower].self, from: data)
            } catch {
                XCTFail("Catch block error")
            }

            expectation.fulfill()

            // Assert
            XCTAssertEqual(followers.count, 1)
        }
        dataTask.resume()

        wait(for: [expectation], timeout: 5)
    }