Contract testing

Contract testing is a form of integration testing where a contract is established between a consumer and a provider. The contract is a collection of requests and responses that the consumer expects to send and receive from the provider. The contract is used to verify that the provider can meet the consumer's expectations.

Contracts can be for synchronous or asynchronous communication, and can be used to verify the behaviour of both HTTP and message-based systems.

Contract tests should cover all provider-consumer relationships with other services that are owned by FCP. Where one side of the contract is not owned by FCP then more traditional provider-driven or even broad integration tests with test instances of those services may be preferred.

Contract tests should mock the immediate dependencies of the contract similar to unit tests.

Service architectures should be written in such a way that reduce the need for these higher risk contracts. For example introducing an FCP managed API gateway between third party services and FCP, would allow all FCP services to contract test against the API gateway abstraction. More complicated end to end testing is then restricted to only the API gateway.

Pact Broker

The Pact Broker is an application for sharing of consumer driven contracts and verification results. It is optimised for use with "pacts" (contracts created by the Pact framework), but can be used for any type of contract that can be serialized to JSON.

Webhooks

Documentation: https://docs.pact.io/pact_broker/webhooks

Through the Pact-Broker CLI:

Open a command window and navigate to the bin folder of the pact-cli and run the following command replacing the variables for your deployment. For more information: https://docs.pact.io/pact_broker/client_cli/readme

pact-broker create-webhook "https://listeners.jenkins-sb.savagebeast.com/job/listeners-acceptance/job/graphql/job/DEVTOOLS-610-test-pact-broker-webhooks/buildWithParameters?os_authType=basic&environment=shared&graphqlHost=shared.graphql.docker.savagebeast.com" --request=POST --broker-base-url=http://localhost:9292 --description='Test 3 Webhook CLI' --contract-content-changed --consumer="Example App" --provider="Example API" --user=username:password --header="accept:application/json"

Through the Pact-Broker UI:

1. Under the column called "Webhook status" click on "Create"
2. Under the heading "Links" Locate "pb:create" in the column called "NON-GET" Click on the "!" symbol.
3. A new window will open to allow the use of HTTP verbs POST, DELETE.

To create the webhook use POST with following body:

Jenkins Example

{
  "description": "Trigger ffc-demo-claim-service Acceptance Test Job on contract_content_changed event from ffc-demo-payment-service",
  "events": [{
    "name": "contract_content_changed"
  }],
  "request": {
    "method": "POST",
    "url": "",
    "headers": {
      "authorization": "Basic "
    }
  }
}

Slack Example

{
  "description": "Trigger to send Slack message on provider-verification-failed event from ffc-demo-payment-service",
  "events": [
    {
      "name": "provider_verification_failed"
    }
  ],
  "request": {
    "method": "POST",
    "url": "",
    "headers": {
      "Content-Type": "application/json"
    },
    "body": {
      "channel": "#generalbuildfailures",
      "username": "webhookbot",
      "text": "Pact verification failed for ${pactbroker.consumerName}/${pactbroker.providerName}: ${pactbroker.pactUrl}",
      "icon_emoji": ":("
    }
  }
}

To delete a Webhook use the DELETE Verb with an empty body.

To test the webhook:

1. Select the webhook using "GET"
2. Under the heading "Links" Locate "pb:execute"

Note

As of writing this guide, there is an issue with the default url used within the UI for executing the API calls.

The current default url uses the internal IP address. This causes the following error:

violates the following Content Security Policy directive: "default-src 'self'". Note that 'connect-src' was not explicitly set, so 'default-src' is used as a fallback.

to resolve the issue, the IP address needs replacing with the DNS domain name.