Testing code

XCTestExample.swift

   func testDataStore() {
        
        let dataSource = iTrackDataStore(searchTerm: "new")
        let expect = expectation(description: "Data store calls APIClient to access server data and returns iTrack data array.")
        
        dataSource.searchForTracks { tracks, error in
            XCTAssert(tracks?.count == 49)
            expect.fulfill()
        }

        waitForExpectations(timeout: 4) { error in
            if let error = error {
                XCTFail("waitForExpectationsWithTimeout errored: \(error)")
            }
        }
    }