Pact is a contract testing tool. Contract testing is a way to ensure that services (such as an API provider and a client) can communicate with each other. Without contract testing, the only way to know that services can communicate is by using expensive and brittle integration tests.

Run Consumer contract Tests

mvn clean test -pl age-consumer

Generated Pact file:

{
  "provider": {
    "name": "dateProvider"
  },
  "consumer": {
    "name": "ageConsumer"
  },
  "interactions": [
    {
      "description": "valid date from provider",
      "request": {
        "method": "GET",
        "path": "/provider/validDate",
        "query": {
          "date": [
            "2001-02-03"
          ]
        },
        "matchingRules": {
          "query": {
            "date": {
              "matchers": [
                {
                  "match": "date",
                  "date": "2001-02-03"
                }
              ],
              "combine": "AND"
            }
          }
        },
        "generators": {
          "body": {
            "date": {
              "type": "Date",
              "format": "2001-02-03"
            }
          }
        }
      },
      "response": {
        "status": 200,
        "headers": {
          "content-type": "application/json",
          "Content-Type": "application/json; charset=UTF-8"
        },
        "body": {
          "month": 8,
          "year": 2000,
          "isValidDate": true,
          "day": 3
        },
        "matchingRules": {
          "body": {
            "$.year": {
              "matchers": [
                {
                  "match": "number"
                }
              ],
              "combine": "AND"
            },
            "$.month": {
              "matchers": [
                {
                  "match": "number"
                }
              ],
              "combine": "AND"
            },
            "$.day": {
              "matchers": [
                {
                  "match": "number"
                }
              ],
              "combine": "AND"
            },
            "$.isValidDate": {
              "matchers": [
                {
                  "match": "type"
                }
              ],
              "combine": "AND"
            }
          },
          "header": {
            "Content-Type": {
              "matchers": [
                {
                  "match": "regex",
                  "regex": "application/json(;\\s?charset=[\\w\\-]+)?"
                }
              ],
              "combine": "AND"
            }
          }
        }
      },
      "providerStates": [
        {
          "name": ""
        }
      ]
    }
  ],
  "metadata": {
    "pactSpecification": {
      "version": "3.0.0"
    },
    "pact-jvm": {
      "version": "4.0.9"
    }
  }
}

Start Pact Broker at default port :8282

docker-compose up -d

Publish Pact Files in Pact Broker

$ cd age-consumer
$ mvn pact:publish

Verify Pacts in Pact Broker at Provider side

mvn clean -Dtest=PactAgeProviderTest test -pl date-provider

Spring Cloud Contract is an umbrella project holds solutions to help users implement contract tests. It has two main modules:

• Spring Cloud Contract Verifier, which is used mainly by the producer side.
• Spring Cloud Contract Stub Runner, which is used by the consumer side.