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A new version featuring Pact Specification v3, a simplified installation and better management of the mock server processes is in active development and can be found at PactSwift. We are currently looking for people to try it out and provide feedback.
This library provides a Swift / Objective C DSL for creating Consumer Pacts. It provides support for Consumer Driven Contract Testing between dependent systems where the integration is based on HTTP (or message queues for some of the implementations).
But why? To test communication boundaries between your app and services. You can view a presentation on how Pact can work in a mobile context here: Yow! Connected 2016 Andrew Spinks - Increasing The Confidence In Your Service Integrations.
Implements Pact Specification v2, including flexible matching.
This DSL relies on the Ruby pact-ruby-standalone (brew tap) to provide the mock service for the tests.
Note: see Upgrading for notes on upgrading from 0.2 to 0.3
brew tap pact-foundation/pact-ruby-standalone
brew install pact-ruby-standalone
This will install the following tools:
pact
pact-broker
pact-message
pact-mock-service
pact-provider-verifier
pact-publish
pact-stub-service
Alternatively you can download and install the pact-ruby-standalone archives for your platform and install as per installation instructions written in Pact Ruby Standalone release notes.
In Xcode, edit your scheme and add pre- and post-actions to Test
to start and stop pact-mock-service
. Make sure you select your target in Provide build settings from the drop down menu.
# Pre-actions
PATH=/path/to/your/standalone/pact/bin:$PATH
pact-mock-service start --pact-specification-version 2.0.0 --log "${SRCROOT}/tmp/pact.log" --pact-dir "${SRCROOT}/tmp/pacts" -p 1234
# Post-actions
PATH=/path/to/your/standalone/pact/bin:$PATH
pact-mock-service stop
Note: your generated Pact files will be dropped into "${SRCROOT}/tmp/pacts"
folder.
Using Carthage
- See the PactSwiftExample
for an example project using
pact-consumer-swift
with Carthage for an iOS target. - See the PactMacOSExample
for an example project using
pact-consumer-swift
through Carthage for a macOS target.
Using CocoaPods
- See the PactObjectiveCExample
for an example project using
pact-consumer-swift
with CocoaPods for an iOS target.
Using Swift Package Manager
- See the PactSwiftPMExample
for an example project using
pact-consumer-swift
library through Swift Package Manager for an executable that runs in terminal.
Write a Unit test similar to the following (NB: this example is using the Quick test framework)
import PactConsumerSwift
...
beforeEach {
animalMockService = MockService(provider: "Animal Service", consumer: "Animal Consumer Swift")
animalServiceClient = AnimalServiceClient(baseUrl: animalMockService!.baseUrl)
}
it("gets an alligator") {
animalMockService!.given("an alligator exists")
.uponReceiving("a request for an alligator")
.withRequest(method:.GET, path: "/alligator")
.willRespondWith(status:200,
headers: ["Content-Type": "application/json"],
body: ["name": "Mary"])
//Run the tests
animalMockService!.run { (testComplete) -> Void in
animalServiceClient!.getAlligator { (alligator) in
expect(alligator.name).to(equal("Mary"))
testComplete()
}
}
}
An optional timeout
(seconds) parameter can be included on the run function. This defaults to 30 seconds.
...
animalMockService!.run(timeout: 60) { (testComplete) -> Void in
animalServiceClient!.getAlligator { (alligator) in
expect(alligator.name).to(equal("Mary"))
testComplete()
}
}
Write a Unit test similar to the following
@import PactConsumerSwift;
...
- (void)setUp {
[super setUp];
self.animalMockService = [[MockService alloc] initWithProvider:@"Animal Provider"
consumer:@"Animal Service Client Objective-C"];
self.animalServiceClient = [[OCAnimalServiceClient alloc] initWithBaseUrl:self.animalMockService.baseUrl];
}
- (void)testGetAlligator {
typedef void (^CompleteBlock)();
[[[[self.animalMockService given:@"an alligator exists"]
uponReceiving:@"oc a request for an alligator"]
withRequestHTTPMethod:PactHTTPMethodGET
path:@"/alligator"
query:nil headers:nil body:nil]
willRespondWithHTTPStatus:200
headers:@{@"Content-Type": @"application/json"}
body: @"{ \"name\": \"Mary\"}" ];
[self.animalMockService run:^(CompleteBlock testComplete) {
Animal *animal = [self.animalServiceClient getAlligator];
XCTAssertEqualObjects(animal.name, @"Mary");
testComplete();
}];
}
An optional timeout
(seconds) parameter can be included on the run function. This defaults to 30 seconds.
...
[self.animalMockService run:^(CompleteBlock testComplete) {
Animal *animal = [self.animalServiceClient getAlligator];
XCTAssertEqualObjects(animal.name, @"Mary");
testComplete();
} timeout:60];
}
Write a Unit Test similar to the following:
import PactConsumerSwift
...
var animalMockService: MockService?
var animalServiceClient: AnimalServiceClient?
override func setUp() {
super.setUp()
animalMockService = MockService(provider: "Animal Provider", consumer: "Animal Service Client")
animalServiceClient = AnimalServiceClient(baseUrl: animalMockService!.baseUrl)
}
func testItGetsAlligator() {
// Prepare the expecated behaviour using pact's MockService
animalMockService!
.given("an alligator exists")
.uponReceiving("a request for alligator")
.withRequest(method: .GET, path: "/alligator")
.willRespondWith(status: 200,
headers: ["Content-Type": "application/json"],
body: [ "name": "Mary" ])
// Run the test
animalMockService!.run(timeout: 60) { (testComplete) -> Void in
self.animalServiceClient!.getAlligator { (response) -> in
XCTAssertEqual(response.name, "Mary")
testComplete()
}
}
}
...
An optional timeout
(seconds) parameter can be included on the run function. Defaults to 30 seconds.
...
// Run the test
animalMockService!.run(timeout: 60) { (testComplete) -> Void in
self.animalServiceClient!.getAlligator { (response) -> in
XCTAssertEqual(response.name, "Mary")
testComplete()
}
}
For an example on how to test over https
see PactSSLSpec.swift.
In addition to verbatim value matching, you have 3 useful matching functions
in the Matcher
class that can increase expressiveness and reduce brittle test
cases.
Matcher.term(matcher, generate)
- tells Pact that the value should match using a given regular expression, usinggenerate
in mock responses.generate
must be a string.Matcher.somethingLike(content)
- tells Pact that the value itself is not important, as long as the element type (valid JSON number, string, object etc.) itself matches.Matcher.eachLike(content, min)
- tells Pact that the value should be an array type, consisting of elements like those passed in.min
must be >= 1.content
may be a valid JSON value: e.g. strings, numbers and objects.
NOTE: One caveat to note, is that you will need to use valid Ruby regular expressions and double escape backslashes.
See the PactSpecs.swift
, PactObjectiveCTests.m
for examples on how to expect error responses, how to use query params, and Matchers.
For more on request / response matching, see [Matching][getting_started/matching].
Xcode's pre-actions and post-actions do not honour non-zero script exits and therefore would not fail your build if publishing to a Pact Broker would fail. If you would like to upload your Pact files to a Pact Broker as part of your CI, we would suggest that you create a separate step in your CI workflow with that responsibility.
See pact-ruby-standalone page for installation instructions and how to use pact-broker
client.
If your setup is correct and your tests run against the pack mock server, then you should see a log file here:
$YOUR_PROJECT/tmp/pact.log
And the generated pacts here:
$YOUR_PROJECT/tmp/pacts/...
Publish your generated pact file(s) to your Pact Broker or a Hosted Pact Broker so your API provider can always retrieve them from one location, even when pacts change. Or even just by simply sending the pact file to your API provider devs so they can used them in their tests of their API responses. See Verifying pacts for more information. For an end-to-end example with a ruby back end service, have a look at the KatKit example.
Also, check out this article on using a dockerized Node.js service that uses provider states.
- The Pact website Pact
- The pact mock server that the Swift library uses under the hood Pact mock service
- A pact broker for managing the generated pact files (so you don't have to manually copy them around!) Pact broker
Please read CONTRIBUTING.md