Karate mock server slow to start up under certain circumstances

[theathlete3141]

Following on from #1395, I found that the presence of "Background" in a mock server feature file appears to affect the start up speed of a mock server

Using the HEAD of the develop branch (after #1395 had been resolved, PR #1408), I have the attached example files which should be added to karate-gatling/src/test/scala.
example.zip

When running a basic Karate-Gatling simulation

class KarateSimulation extends Simulation {

  val mock = Properties.propOrEmpty("mock")
  val feature = "classpath:example/mockServer" + mock + ".feature"
  val server = MockServer.feature(feature).build()
  val serverUrl = "http://localhost:" + server.getPort
  System.setProperty("server.url", serverUrl)

  val example = scenario("example")
    .exec(karateFeature("classpath:example/example.feature"))

  setUp(
    example.inject(rampUsers(100) during (10 seconds))
  )
}

With example.feature

Feature:

  Scenario:
    * url karate.properties['server.url']
    * path ''
    * method get
    * status 200
    * match response == { success: true }

Against the mock server mockServer1.feature:

Feature:

  Scenario: pathMatches('')
    * def response = { success: true }

And ran using:

mvn test -D gatling.simulationClass=example.KarateSimulation -D mock=1

Then there is a small (~1s) gap between the first users and first requests.

For comparison, a pure Gatling simulation doesn't do this:

class GatlingSimulation extends Simulation {

  val mock = Properties.propOrEmpty("mock")
  val feature = "classpath:example/mockServer" + mock + ".feature"
  val server = MockServer.feature(feature).build()
  val serverUrl = "http://localhost:" + server.getPort
  System.setProperty("server.url", serverUrl)
  val protocol = http.baseUrl(serverUrl)

  val example = scenario("example")
    .exec(
      http("GET /")
        .get("/")
        .check(status.is(200))
        .check(jsonPath("$.success").is("true"))
    )

  setUp(
    example.inject(rampUsers(100) during (10 seconds)).protocols(protocol)
  )
}

mvn test -D gatling.simulationClass=example.GatlingSimulation -D mock=1

I found that this can be fixed by adding a non-empty "Background" to the mock server:
mockServer2.feature

Feature:

  Background:
    * print 'Background'

  Scenario: pathMatches('')
    * def response = { success: true }

Ran using:

mvn test -D gatling.simulationClass=example.KarateSimulation -D mock=2

However, an empty "Background" displays the original problem
mockServer3.feature

Feature:

  Background:

  Scenario: pathMatches('')
    * def response = { success: true }

Ran using:

mvn test -D gatling.simulationClass=example.KarateSimulation -D mock=3

[ptrthomas]

closing as wontfix these are called mocks for a reason