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AliSoftware edited this page Dec 3, 2014 · 41 revisions

Simple examples

Stub all requests with some given NSData

With the code below, every network request (because you returned YES in the first block) will return a stubbed response containing the data "Hello World!":

[OHHTTPStubs stubRequestsPassingTest:^BOOL(NSURLRequest *request) {
    return YES; // Stub ALL requests without any condition
} withStubResponse:^OHHTTPStubsResponse*(NSURLRequest *request) {
    // Stub all those requests with "Hello World!" string
    NSData* stubData = [@"Hello World!" dataUsingEncoding:NSUTF8StringEncoding];
    return [OHHTTPStubsResponse responseWithData:stubData statusCode:200 headers:nil];
}];

Note that in practice, it is not recommended to directly return YES in the first block and thus stub all requests, because third-party frameworks & SDKs (like Crashlytics, etc) may also send requests and you probably don't want them to receive your own stubbed response (which won't make sense for them anyway).

That's why it's preferred to explicitly use a computed condition in this first block, like in the examples below

Stub only requests to your WebService

This is typically useful in your Unit Tests to only stub specific requests targeted to a given host or WebService, for example.

With the code below, only requests to the mywebservice.com host will be stubbed. Requests to any other host will hit the real world:

[OHHTTPStubs stubRequestsPassingTest:^BOOL(NSURLRequest *request) {
    return [request.URL.host isEqualToString:@"mywebservice.com"];
} withStubResponse:^OHHTTPStubsResponse*(NSURLRequest *request) {
    // Stub it with our "wsresponse.json" stub file
    return [OHHTTPStubsResponse responseWithFileAtPath:OHPathForFileInBundle(@"wsresponse.json",nil)
            statusCode:200 headers:@{@"Content-Type":@"application/json"}];
}];

This example also demonstrate how to easily return the content of a given file in your application bundle. This is useful if you have all your fixtures (stubbed responses for your Unit Tests) in your Xcode project linked with your Unit Test target.

Note: You may even put all your fixtures in a custom bundle (let's call it Fixtures.bundle) and then use the helper macros to get it: OHPathForFileInBundle(@"wsresponse.json",OHResourceBundle(@"Fixtures")).
Some people also like having their own macro for that, e.g. #define fixture(x) OHPathForFileInBundle(@ #x ".json",OHResourceBundle(@"Fixtures")) so that they can simply use fixture(wsresponse) in their code.

Stub requests with a JSON object

As it is common for a lot of WebServices to use the JSON format in their response body, OHHTTPStubs comes with a convenience method (defined as a category in OHHTTPStubs+JSON.) to build a response from a JSON object.

In practice, this convenience method simply use NSJSONSerialization to transform the NSDictionary or NSArray to JSON, and automatically adds the Content-Type: application/json header if there is no Content-Type header defined.

[OHHTTPStubs stubRequestsPassingTest:^BOOL(NSURLRequest *request) {
    return [request.URL.host isEqualToString:@"mywebservice.com"];
} withStubResponse:^OHHTTPStubsResponse*(NSURLRequest *request) {
    NSDictionary* obj = @{ @"key1": @"value1", @"key2": @[@"value2A", @"value2B"] };
    return [OHHTTPStubsResponse responseWithJSONObject:obj statusCode:200 headers:nil];
}];

Set request and response time

You can simulate a slow network by setting the requestTime and/or responseTime properties of your OHHTTPStubsResponse. This is useful to check that your user interface does not freeze when you have bad network conditions, and that you have all your activity indicators working while waiting for responses.

You may use the commodity chainable setters responseTime: and requestTime:responseTime: to set those values and easily chain method calls:

[OHHTTPStubs stubRequestsPassingTest:^BOOL(NSURLRequest *request) {
    return [request.URL.host isEqualToString:@"mywebservice.com"];
} withStubResponse:^OHHTTPStubsResponse*(NSURLRequest *request) {
    return [[OHHTTPStubsResponse responseWithJSONObject:someDict statusCode:200 headers:nil]
            requestTime:1.0 responseTime:3.0];
}];

OHHTTPStubs will wait requestTime before sending the NSHTTPURLResponse, and then start sending chunks of the stub data regularly during the period of responseTime, to simulate the slow network.

In the end, you will only have the full content of your stub data after requestTime+responseTime (time after which the completion block or connectionDidFinishLoading: delegate method will be called).

Note: You can specify a network speed instead of a responseTime by using a negative value. See below.

Simulate a down network

You may also return a network error for your stub. For example, you can easily simulate an absence of network connection like this:

NSError* notConnectedError = [NSError errorWithDomain:NSURLErrorDomain code:kCFURLErrorNotConnectedToInternet userInfo:nil];
[OHHTTPStubsResponse responseWithError:notConnectedError];

Advanced Usage

Use macros to build your fixtures path

OHHTTPStubsResponse.h includes a useful set of macros to build a path to your fixtures easily, like OHPathForFileInBundle, OHPathForFileInDocumentsDir and OHResourceBundle. You are encouraged to use them to build your path more easily.

Especially, they use [NSBundle bundleForClass:self.class] to reference your app bundle (and not [NSBundle mainBundle] as one may think), so that they still work with OCUnit and XCTestKit when unit-testing your app in the Simulator.

Using download speed instead of responseTime

When building the OHHTTPStubsResponse object, you can specify a response time (in seconds) so that the sending of the fake response will be spread over time. This allows you to simulate a slow network for example. (see "Set request and response time")

If you specify a negative value for the responseTime parameter, instead of being interpreted as a time in seconds, it will be interpreted as a download speed in KBytes/s. In that case, the response time will be computed using the length of the response's data to simulate the indicated download speed.

The OHHTTPStubsResponse header defines some constants for standard download speeds:

OHHTTPStubsDownloadSpeedGPRS   =    -7 =    7 KB/s =    56 kbps
OHHTTPStubsDownloadSpeedEDGE   =   -16 =   16 KB/s =   128 kbps
OHHTTPStubsDownloadSpeed3G     =  -400 =  400 KB/s =  3200 kbps
OHHTTPStubsDownloadSpeed3GPlus =  -900 =  900 KB/s =  7200 kbps
OHHTTPStubsDownloadSpeedWifi   = -1500 = 1500 KB/s = 12000 kbps

Example:

return [[OHHTTPStubsResponse responseWithData:nil statusCode:400 headers:nil]
        responseTime:OHHTTPStubsDownloadSpeed3G];

Stack multiple stubs and remove installed stubs

  • You can call stubRequestsPassingTest:withStubResponse: multiple times. It will just add the stubs in an internal list of stubs.

This may be useful to install different stubs in various places in your code, or to separate different stubbing conditions more easily. See the OHHTTPStubsDemo project for a typical example.

When a network request is performed by the system, the stubs are tested in the reverse order that they have been added, the last added stub having priority over the first added ones. The first stub that returns YES for the first parameter of stubRequestsPassingTest:withStubResponse: is then used to reply to the request.

  • You can remove any given stub with the removeStub: method. This method takes as a parameter the id<OHHTTPStubsDescriptor> object returned by stubRequestsPassingTest:withStubResponse: (Note: this returned object is already retained by OHHTTPStubs while the stub is installed, so you should keep it in a __weak variable so it is properly released from memory once removed).
  • You can remove the latest added stub with the removeLastStub method.
  • You can also remove all stubs at once with the removeAllStubs method.

This last one is useful when using OHHTTPStubs in your Unit Tests, to remove all installed stubs at the end of each of your test case to avoid stubs installed in one test case to be still installed for the next test case.

- (void)tearDown
{
    [OHHTTPStubs removeAllStubs];
    [super tearDown];
}

Name your stubs and log their activation

You can add a name of your choice to your stubs. The only purpose of this is to easily identify your stubs for debugging, like when displaying them in the console.

id<OHHTTPStubsDescriptor> stub = [OHHTTPStubs stubRequestsPassingTest:... withStubResponse:...];
stub.name = @"Stub for text files";

You can even imagine applying the .name = ... affectation directly (if you don't need to use the returned id<OHHTTPStubsDescriptor> otherwise), for a more concise syntax:

[OHHTTPStubs stubRequestsPassingTest:^BOOL(NSURLRequest *request) {
   ...
} withStubResponse:^OHHTTPStubsResponse*(NSURLRequest *request) {
   ...
}].name = @"Stub for text files";

You can then list all the installed stubs using [OHHTTPStubs allStubs], which returns an array of id<OHHTTPStubsDescriptor> objects so you can display their name on the console. This is useful to check that you didn't forget to remove some previous stubs that are still installed for example.

You can also setup a block that gets executed each time a request has been stubbed, using onStubActivation: method. This is typically useful to log the stub being used for each request:

[OHHTTPStubs onStubActivation:^(NSURLRequest *request, id<OHHTTPStubsDescriptor> stub) {
    NSLog(@"%@ stubbed by %@", request.URL, stub.name);
}];

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