Pact Consumer is used by projects that are consumers of an API.

Most projects will want to use pact-consumer via one of the test framework specific projects. If your favourite framework is not implemented, this module should give you all the hooks you need.

Provides a DSL for use with Java to build consumer pacts.

Dependency

The library is available on maven central using:

• group-id = au.com.dius.pact
• artifact-id = consumer

DSL Usage

Example in a JUnit test:

import au.com.dius.pact.model.MockProviderConfig;

import au.com.dius.pact.model.RequestResponsePact;

import org.apache.http.entity.ContentType;

import org.jetbrains.annotations.NotNull;

import org.junit.Test;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import static au.com.dius.pact.consumer.ConsumerPactRunnerKt.runConsumerTest;

import static org.junit.Assert.assertEquals;

public class PactTest {

@Test

public void testPact() {

RequestResponsePact pact = ConsumerPactBuilder

.consumer("Some Consumer")

.hasPactWith("Some Provider")

.uponReceiving("a request to say Hello")

.path("/hello")

.method("POST")

.body("{\"name\": \"harry\"}")

.willRespondWith()

.status(200)

.body("{\"hello\": \"harry\"}")

.toPact();

MockProviderConfig config = MockProviderConfig.createDefault();

PactVerificationResult result = runConsumerTest(pact, config, new PactTestRun() {

@Override

public void run(@NotNull MockServer mockServer) throws IOException {

Map expectedResponse = new HashMap();

expectedResponse.put("hello", "harry");

assertEquals(expectedResponse, new ConsumerClient(mockServer.getUrl()).post("/hello",

"{\"name\": \"harry\"}", ContentType.APPLICATION_JSON));

}

});

if (result instanceof PactVerificationResult.Error) {

throw new RuntimeException(((PactVerificationResult.Error)result).getError());

}

assertEquals(PactVerificationResult.Ok.INSTANCE, result);

}

}

The DSL has the following pattern:

.consumer("Some Consumer")

.hasPactWith("Some Provider")

.given("a certain state on the provider")

.uponReceiving("a request for something")

.path("/hello")

.method("POST")

.body("{\"name\": \"harry\"}")

.willRespondWith()

.status(200)

.body("{\"hello\": \"harry\"}")

.uponReceiving("another request for something")

.path("/hello")

.method("POST")

.body("{\"name\": \"harry\"}")

.willRespondWith()

.status(200)

.body("{\"hello\": \"harry\"}")

.

.

.

.toPact()

You can define as many interactions as required. Each interaction starts with uponReceiving followed by willRespondWith. The test state setup with given is a mechanism to describe what the state of the provider should be in before the provider is verified. It is only recorded in the consumer tests and used by the provider verification tasks.

Building JSON bodies with PactDslJsonBody DSL

The body method of the ConsumerPactBuilder can accept a PactDslJsonBody, which can construct a JSON body as well as define regex and type matchers.

For example:

PactDslJsonBody body = new PactDslJsonBody()

.stringType("name")

.booleanType("happy")

.hexValue("hexCode")

.id()

.ipAddress("localAddress")

.numberValue("age", 100)

.timestamp();

DSL Matching methods

The following matching methods are provided with the DSL. In most cases, they take an optional value parameter which will be used to generate example values (i.e. when returning a mock response). If no example value is given, a random one will be generated.

method	description
string, stringValue	Match a string value (using string equality)
number, numberValue	Match a number value (using Number.equals)*
booleanValue	Match a boolean value (using equality)
stringType	Will match all Strings
numberType	Will match all numbers*
integerType	Will match all numbers that are integers (both ints and longs)*
decimalType	Will match all real numbers (floating point and decimal)*
booleanType	Will match all boolean values (true and false)
stringMatcher	Will match strings using the provided regular expression
timestamp	Will match string containing timestamps. If a timestamp format is not given, will match an ISO timestamp format
date	Will match string containing dates. If a date format is not given, will match an ISO date format
time	Will match string containing times. If a time format is not given, will match an ISO time format
ipAddress	Will match string containing IP4 formatted address.
id	Will match all numbers by type
hexValue	Will match all hexadecimal encoded strings
uuid	Will match strings containing UUIDs
includesStr	Will match strings containing the provided string
equalsTo	Will match using equals
matchUrl	Defines a matcher for URLs, given the base URL path and a sequence of path fragments. The path fragments could be
strings or regular expression matchers

* Note: JSON only supports double precision floating point values. Depending on the language implementation, they may parsed as integer, floating point or decimal numbers.

Ensuring all items in a list match an example

Lots of the time you might not know the number of items that will be in a list, but you want to ensure that the list has a minimum or maximum size and that each item in the list matches a given example. You can do this with the arrayLike, minArrayLike and maxArrayLike functions.

function	description
eachLike	Ensure that each item in the list matches the provided example
maxArrayLike	Ensure that each item in the list matches the provided example and the list is no bigger than the provided max
minArrayLike	Ensure that each item in the list matches the provided example and the list is no smaller than the provided min

For example:

DslPart body = new PactDslJsonBody()

.minArrayLike("users")

.id()

.stringType("name")

.closeObject()

.closeArray();

This will ensure that the users list is never empty and that each user has an identifier that is a number and a name that is a string.

Matching JSON values at the root

For cases where you are expecting basic JSON values (strings, numbers, booleans and null) at the root level of the body and need to use matchers, you can use the PactDslJsonRootValue class. It has all the DSL matching methods for basic values that you can use.

For example:

.consumer("Some Consumer")

.hasPactWith("Some Provider")

.uponReceiving("a request for a basic JSON value")

.path("/hello")

.willRespondWith()

.status(200)

.body(PactDslJsonRootValue.integerType())

Root level arrays that match all items

If the root of the body is an array, you can create PactDslJsonArray classes with the following methods:

function	description
arrayEachLike	Ensure that each item in the list matches the provided example
arrayMinLike	Ensure that each item in the list matches the provided example and the list is no bigger than the provided max
arrayMaxLike	Ensure that each item in the list matches the provided example and the list is no smaller than the provided min

For example:

PactDslJsonArray.arrayEachLike()

.date("clearedDate", "mm/dd/yyyy", date)

.stringType("status", "STATUS")

.decimalType("amount", 100.0)

.closeObject()

This will then match a body like:

[ {

"clearedDate" : "07/22/2015",

"status" : "C",

"amount" : 15.0

}, {

"clearedDate" : "07/22/2015",

"status" : "C",

"amount" : 15.0

}, {

"clearedDate" : "07/22/2015",

"status" : "C",

"amount" : 15.0

} ]

Matching arrays of arrays

For the case where you have arrays of arrays (GeoJSON is an example), the following methods have been provided:

function	description
eachArrayLike	Ensure that each item in the array is an array that matches the provided example
eachArrayWithMaxLike	Ensure that each item in the array is an array that matches the provided example and the array is no bigger than the provided max
eachArrayWithMinLike	Ensure that each item in the array is an array that matches the provided example and the array is no smaller than the provided min

For example (with GeoJSON structure):

new PactDslJsonBody()

.stringType("type","FeatureCollection")

.eachLike("features")

.stringType("type","Feature")

.object("geometry")

.stringType("type","Point")

.eachArrayLike("coordinates") // coordinates is an array of arrays

.decimalType(-7.55717)

.decimalType(49.766896)

.closeArray()

.closeArray()

.closeObject()

.object("properties")

.stringType("prop0","value0")

.closeObject()

.closeObject()

.closeArray()

This generated the following JSON:

{

"features": [

{

"geometry": {

"coordinates": [[-7.55717, 49.766896]],

"type": "Point"

},

"type": "Feature",

"properties": { "prop0": "value0" }

}

],

"type": "FeatureCollection"

}

and will be able to match all coordinates regardless of the number of coordinates.

Matching any key in a map

The DSL has been extended for cases where the keys in a map are IDs. For an example of this, see #313. In this case you can use the eachKeyLike method, which takes an example key as a parameter.

For example:

DslPart body = new PactDslJsonBody()

.object("one")

.eachKeyLike("001", PactDslJsonRootValue.id(12345L)) // key like an id mapped to a matcher

.closeObject()

.object("two")

.eachKeyLike("001-A") // key like an id where the value is matched by the following example

.stringType("description", "Some Description")

.closeObject()

.closeObject()

.object("three")

.eachKeyMappedToAnArrayLike("001") // key like an id mapped to an array where each item is matched by the following example

.id("someId", 23456L)

.closeObject()

.closeArray()

.closeObject();

For an example, have a look at WildcardKeysTest.

NOTE: The eachKeyLike method adds a * to the matching path, so the matching definition will be applied to all keys of the map if there is not a more specific matcher defined for a particular key. Having more than one eachKeyLike condition applied to a map will result in only one being applied when the pact is verified (probably the last).

Further Note: From version 3.5.22 onwards pacts with wildcards applied to map keys will require the Java system property "pact.matching.wildcard" set to value "true" when the pact file is verified.

Matching on paths

You can use regular expressions to match incoming requests. The DSL has a matchPath method for this. You can provide a real path as a second value to use when generating requests, and if you leave it out it will generate a random one from the regular expression.

For example:

.given("test state")

.uponReceiving("a test interaction")

.matchPath("/transaction/[0-9]+") // or .matchPath("/transaction/[0-9]+", "/transaction/1234567890")

.method("POST")

.body("{\"name\": \"harry\"}")

.willRespondWith()

.status(200)

.body("{\"hello\": \"harry\"}")

Matching on headers

You can use regular expressions to match request and response headers. The DSL has a matchHeader method for this. You can provide an example header value to use when generating requests and responses, and if you leave it out it will generate a random one from the regular expression.

For example:

.given("test state")

.uponReceiving("a test interaction")

.path("/hello")

.method("POST")

.matchHeader("testreqheader", "test.*value")

.body("{\"name\": \"harry\"}")

.willRespondWith()

.status(200)

.body("{\"hello\": \"harry\"}")

.matchHeader("Location", ".*/hello/[0-9]+", "/hello/1234")

Matching on query parameters

You can use regular expressions to match request query parameters. The DSL has a matchQuery method for this. You can provide an example value to use when generating requests, and if you leave it out it will generate a random one from the regular expression.

For example:

.given("test state")

.uponReceiving("a test interaction")

.path("/hello")

.method("POST")

.matchQuery("a", "\\d+", "100")

.matchQuery("b", "[A-Z]", "X")

.body("{\"name\": \"harry\"}")

.willRespondWith()

.status(200)

.body("{\"hello\": \"harry\"}")

Forcing pact files to be overwritten

By default, when the pact file is written, it will be merged with any existing pact file. To force the file to be overwritten, set the Java system property pact.writer.overwrite to true.

Having values injected from provider state callbacks

You can have values from the provider state callbacks be injected into most places (paths, query parameters, headers, bodies, etc.). This works by using the V3 spec generators with provider state callbacks that return values. One example of where this would be useful is API calls that require an ID which would be auto-generated by the database on the provider side, so there is no way to know what the ID would be beforehand.

The following DSL methods allow you to set an expression that will be parsed with the values returned from the provider states:

For JSON bodies, use valueFromProviderState.
For headers, use headerFromProviderState.
For query parameters, use queryParameterFromProviderState.
For paths, use pathFromProviderState.

For example, assume that an API call is made to get the details of a user by ID. A provider state can be defined that specifies that the user must be exist, but the ID will be created when the user is created. So we can then define an expression for the path where the ID will be replaced with the value returned from the provider state callback.

.pathFromProviderState("/api/users/${id}", "/api/users/100")

You can also just use the key instead of an expression:

.valueFromProviderState('userId', 'userId', 100) // will look value using userId as the key