Beats

A heart rate app for iOS for stationary workouts (treadmill, circuit classes, etc.). Built because I couldn't find a nicely designed, simple heart rate tracker for workouts that didn't involved tracking distance rather than time.

Currently tested and compatible with:

• Polar H7 Heart Rate Monitor
• More to follow ...

Technology

• Swift 2
• Xcode 7
• XCTest
• UITesting
• Core Bluetooth

One of the biggest technical challenges so far has been creating a mock version of the Core Bluetooth API, made particularly difficult as key objects have no public initializers.

Designed using Sketch.

To Do

For full development roadmap, head over to the project board Trello.

Future plans and features include:

• Record workout
• Save workout
• Display workout on scrolling graph
• Pull HeartRateKit out into a framework
• Personalised heart rate zones

Resources

• Core Bluetooth Programming Guide

• Core Bluetooth Framework Reference

• Polar Developer Resources

• Bluetooth Developer Portal: Guidance on standards for heart rate measurement services and characteristics.

• RZBluetooth: An open source Objective-C wrapper for Core Bluetooth. Used for inspiration to understand how to test and mock Core Bluetooth. Also I submitted pull request to add Swift example code.

Code Snippet

A helper method to run asynchronous tests on methods that don't have a closure in the argument. The only example code for XCTestExpectation was for networking code, like this from Big Nerd Ranch, but I need to test CoreBluetooth methods which did not include a completionHandler in the method signature. In order to avoid altering the CoreBluetooth code purely for testing purposes I wrote this asyncTest function which is used throughout my tests.

extension XCTestCase {

    func asyncTest(completion: () -> Void, wait: Int64){
        let time = dispatch_time(dispatch_time_t(DISPATCH_TIME_NOW), wait * Int64(NSEC_PER_SEC))

        dispatch_after(time, dispatch_get_main_queue()) {
            completion()
        }
    }

}

Example usage:

func testReceivesUpdatesOnHeartRate() {
    weak var expectation = expectationWithDescription("Should see a pulse")

    let completion = { () -> Void in
        XCTAssertTrue(self.mockBluetoothController.hrNotificationReceived)
        expectation?.fulfill()
    }

    mockPeripheral.setHeartRateMode(.SteadyResting)
    asyncTest(completion, wait: 5)

    waitForExpectationsWithTimeout(5.5, handler: nil)
}