A testable RxSwift wrapper around MultipeerConnectivity
6 min read
A testable RxSwift wrapper around MultipeerConnectivity
RxMultipeer is a RxSwift wrapper for MultipeerConnectivity.
Using the adapter pattern, we can test multipeer code with heavy mocking. In effect, we are trying to isolate all the untestable bits of MultipeerConnectivity into one library.
This library also gives you the flexibility to swap out the underlying mechanics of p2p with some other protocol such as websockets. At the moment it only comes with support for Apple’s MultipeerConnectivity, however you can easily write your own adapters for different protocols.
Installation
Carthage
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3.0
“>
github "RxSwiftCommunity/RxMultipeer" ~> 3.0
Example code
For a working example check out the RxMultipeer Example folder.
// See the link above,// You'll need to define a new build configuration and give it the `TESTING` flaglet name = UIDevice.currentDevice().name
#if TESTING
typealiasI= MockIden
let client =CurrentClient(session: MockSession(name: name))
#elsetypealiasI= MCPeerID
let client =CurrentClient(session: MultipeerConnectivitySession(
displayName: name,
serviceType: "multipeerex",
idenCacheKey: "com.rxmultipeer.example.mcpeerid",
encryptionPreference: .None))
#endif
When testing, use preprocesser macros to ensure that your code uses a MockSession instance instead of MultipeerConnectivitySession one. In order to achieve this you need to use preprocessor flags and swap out anywhere that references Client (because T will be different depending on whether you are testing or not.) First you will need to set up a new build configuration, and then you can use preprocessor macros like so:
let name = UIDevice.currentDevice().name
#if TESTING
typealiasI= MockIden
let client =CurrentClient(session: MockSession(name: name))
#elsetypealiasI= MCPeerID
let client =CurrentClient(session: MultipeerConnectivitySession(
displayName: name,
serviceType: "multipeerex",
idenCacheKey: "com.rxmultipeer.example.mcpeerid",
encryptionPreference: .None))
#endif
Don’t worry, you should only really need preprocessor macros in one centralized place, the type of your client can be inferred by the compiler thereafter.
Mocking other nearby peers in the test environment then becomes as simple as creating other CurrentClient(session: MockSession(name: "other")). For example, if your app is running in a testing environment the following code will mock a nearby client:
<div class="highlight highlight-source-swift position-relative" data-snippet-clipboard-copy-content="let disposeBag: DisposeBag
let otherclient = CurrentClient(session: MockSession(name: " mockedother")) Accept all connections otherclient.startAdvertising() otherclient.incomingConnections() .subscribeNext { (client, context, respond) in respond(true) } .addDisposableTo(disposeBag) Starting from version 3.0.0 the following handler needs to be implemented for this library to work: otherclient.incomingCertificateVerifications() .subscribeNext { (client, certificateChain, respond) in respond(true) } .addDisposableTo(disposeBag) Respond to all messages with 'Roger' otherclient.receive() .map { (client: Client, string: String) in otherclient.send(toPeer: client, “Roger”) }
.concat()
.subscribeNext { _ in print(“Response sent”) }
.addDisposableTo(disposeBag)
“>
let disposeBag: DisposeBag
let otherclient =CurrentClient(session: MockSession(name: "mockedother"))
// Accept all connections
otherclient.startAdvertising()
otherclient.incomingConnections()
.subscribeNext { (client, context, respond) inrespond(true) }
.addDisposableTo(disposeBag)
// Starting from version 3.0.0 the following handler needs to be implemented// for this library to work:
otherclient.incomingCertificateVerifications()
.subscribeNext { (client, certificateChain, respond) inrespond(true) }
.addDisposableTo(disposeBag)
// Respond to all messages with 'Roger'
otherclient.receive()
.map { (client: Client<MockIden>, string: String) in otherclient.send(toPeer: client, "Roger") }
.concat()
.subscribeNext { _inprint("Response sent") }
.addDisposableTo(disposeBag)
Breaking changes
Version 3.0.0
Starting from version 3.0.0, incomingCertificateVerifications() -> Observable Void)> was introduced. This needs to be implemented in order for mock and real connections to work. Behaviour prior to this update can be reproduced by simply accepting all certificates:
