Smart Stub version 0.10.3

The Smart Stub provides some powerful capabilites:

• built-in swagger validation
• built-in state transition validation
• built-in sla latency
• ability to prime responses
• ability to globally substitute strings in all responses

Build instructions

sbt reload clean assembly // build and run tests sbt publish // push the jar to s3

Usage

Engineers should create an Object (e.g. MyStub.scala) which extends SmartStub and then:

• override setUpMocks() with your stubb mappings
• add a driver method
• add a swagger json or yaml under resources
• add a state model under resources (optional)
• add an sla config under resources (optional)

Example

The project contains StubTests.scala which offers an example of mocking and test using SmartStub.

A driver method with and without state and sla

   def configureAndStart(): Unit = {
        MyStub.configureStub("8089", "src/test/resources/", "src/test/resources/openApi.json", "src/test/resources/stateModel.json", "idle", "src/test/resources/sla.json")
        MyStub.start
      }
    
    def configureAndStart(): Unit = {   
         MyStub.configureStub("8089", null, "src/test/resources/openApi.json", null, null, null)
         MyStub.start
      }  

Wiremock mappings

    override def setUpMocks(cannedResponsesPath: String): Unit  = {

      wireMockServer.stubFor(post(urlMatching(".*/cars"))
             .withRequestBody(equalToJson("{\"action\":\"drive\"}",true,true))
             .willReturn(
               aResponse()
                 .withTransformerParameter("nextState", "moving")
                 .withBody("""{"response":"hello"}""")
                 .withStatus(200)));
    }
    

The optional withTransformerParameter() method will indicate the state this action should place you in
If you are not interested in state, use withTransformerParameter("nextState", "any") or omit the line.

The mappings can be added on the fly by the tests.

Prime next response

If you want to replace the whole response with your own you can tell Smart Stub by Posting a primed response
as follows:

    doPost(url+MyStub.PRIMED_RESPONSE_URL+"?"+MyStub.RESPONSE_STATUS_QUERY_PARAM+"=200",  """{"response":"hello"}""")

The next call to this stub will return this request's body and headers and the passed status

You can create a series of responses by calling this multiple times and the stub will read FIFO

Of course, if you have a wiremock handle, you can  add mock stubs on the fly using the wiremock API.

The alternative approach to priming is to rely on canned responses from the stub. The canned approach
 would benefit from a documented and distrubuted list of known canned identifiers (users, products etc)
 so that testing can lever consistency between separate stubs.
 
If you just want to tweak the canned response:
- make a call to the stub service or access the canned json in the jar
- tweak the response payload
- prime the next response with the tweaked payload

String substitute

If you only want to globally tweak something in the canned response you can tell Smart Stub to perform a
simple replaceAll for a given string for all responses. This would be useful, for example, if you want
to use a username diffferent to the one in the canned response.

    doGet(url+MyStub.RESPONSE_SUBSTITUTE_STRING_URL+"?"+MyStub.RESPONSE_SUBSTITUTE_TARGET_QUERY_PARAM+"=<from>&"+MyStub.RESPONSE_SUBSTITUTE_WITH_QUERY_PARAM+"=<to>")

State model

The stateModel.json will be of the following format:

   {
     "stateTransitions": [
         {
           "prestate": "<some state>",
           "poststate": "<some state>"
         },
         {
           "prestate": "<some state>",
           "poststate": "<some state>"
         }
     ]
   }

If you don't want any state you can set-up the model with:
"prestate": "any", "poststate": "any"

SLA

The sla.json be of the following format:

{  
  "slaPoints": [
    {
      "endpoint": "car",
      "action": "post",
      "latency": "1000:80,5000:20"
    }
  ]
}

Latency is of the format of a list of delay:percentage If you don't want any sla you can set-up the model with no endpoint data.

NB. latency is in milliseconds.

Errors

• An invalid request payload will return a 400 with an error and an "Invalid contract" message
• An invalid response (from the stub) will also result in a 400 with an error and an "Invalid contract" message
• An invalid state transition will (you guessed it) return a 400 with an error and an "Invalid state transition" message

License

This project is licensed under the APACHE License - see the LICENSE file for details

Acknowledgments

The awesome Wiremock team