A Brief overview about contract testing
Contract testing, is a testing carried out between two parties (Producer & Consumer). It has more focus on any changes from producer side, which should not cause failure on consumer side. It is NEITHER "Functional Testing", It is NOR "API Testing"
A general example of producer and consumer.
- A Inventory service which produce data for order service
- Order service which consume data from inventory service and create order based on that
Another example (This is example, came to mind and created services for that :) :
- A Tweet/comment API generally produce data about various topic.
- Entertainment service (imdb kind of) which basically uses comments and tweets and show it.
Produce side
- Tweet/Comment service produce data in json format (GET- localhost:8181/tweet/)
[ { "userID": "1", "userName": "@Austin174", "tweetDescription": "#GameOfThrones:Why is it that when one man builds a wall, the next man immediately needs to know what's on the other side?" }, { "userID": "2", "userName": "@Thanh157", "tweetDescription": "#Friends:Raspberries? Good. Ladyfingers? Good. Beef? GOOD!" } ] - To invoke producer service
mvn clean spring-boot:runNote: Default it runs on "8181", you can changed it by providing from command line.
Consumer Side
- Entertainment service create shows belong to various categories. (POST- localhost:8081/showlocalhost:8081/show)
{ "showID":"3", "categoryName":"Non-Fictions", "showName":"Friends" } - Fetch all created shows (GET- localhost:8081/show)
- It fetches data from tweet services, and showed filtered tweet in th form of Posts (GET- localhost:8081/posts/{showID })
- To Invoke consumer service
mvn clean spring-boot:run
Testing side of Produce and Consumer sides: Consumer Side
- Invoke
mvn clean test, It will run all tests (UT/IT/Contract tests) at consumer side. - Pact file will be stored in '/target/pact'
- Generated pact file to be shared with Publisher (Upload shared location github/s3) or use cool way of it doing it using pact-broker (For further info Please refer [https://github.com/DiUS/pact_broker-docker]).
- To publish document on pact broker
mvn pact:publish
Publisher Side
- Invoke
mvn clean test, It will run all tests (UT/IT) at producer side. - To invoke contract tests to producer side
mvn pact:verify(Provided you share location either pactFile/pactUrl in maven-producer-plugin).
Further improvements
- Setting up webhooks to pact-broker, so it will shoot contract tests seamlessly between producer and consumer.
More about contact testing: