While running Karate(1.0.1) tests from Spock, System property that was set in mock ends up undefined in karate.properties['message']

I cloned your project and noticed a few outdated things (Groovy, Spock and GMaven+ versions). Upgrading them did not change the outcome, I can still reproduce your problem.

A also noticed that in your two branches the POM differs in more than just the Karate version number, also the dependencies differ. If I use the ones from the 1.0.1 branch, tests do not work under 0.9.5 anymore. So I forked your project and sent you two pull requests for each branch with a dependency setup working identically for both Karate versions. Now the branches really just differ in the Karate version number:

https://github.com/kriegaex/spock-karate-example/compare/karate-0.9.5...kriegaex:karate-1.0.1

BTW, for some reason I had to compile your code running JDK 11, JDK 16 did not work. GMaven+ complained about Java 16 groovy class files (bytecode version 60.0), even though GMaven+ should have used target level 11. No idea what this is about. Anyway, on Java 11 I can reproduce your problem. As the Spock version is identical for both branches, I guess the problem is within Karate itself. I recommend to open an issue there, linking to your GitHub project (after you have accepted my PRs). Spock definitely sets the system property, I have added more log output into the stubbing closure order to verify that. Maybe this is an issue concerning how and when Karate communicates with Spock.

Update: Peter Thomas suggested in his answer to store the value to be transferred to the feature in a Java object and access that one from the feature after the Spock test has set it. I guess, he means something like this:

https://github.com/kriegaex/spock-karate-example/commit/ca88e3da

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class ApiTestRunnerSpec extends Specification {

    @LocalServerPort
    private int port

    @SpringBean
    MessageLogger messageLogger = Mock() {
        1 * logMessage(_ as String) >> { String message ->
            assert message != null
            MessageHolder.INSTANCE.message = message
        }
    }

    def "setup"() {
        System.out.println("Running on port: " + port)
        System.setProperty("server.port", "" + port)
    }

    def "Run Mock ApiTest"() {
        given:
        Results results = Runner
          .path("classpath:")
          .systemProperty("foo", "bar")
          .tags("~@ignore")
          .parallel(5)

        expect:
        results
    }
    
    static class MessageHolder {
        public static final MessageHolder INSTANCE = new MessageHolder()
        private String message

        private MessageHolder() {}

        String getMessage() {
            return message
        }

        void setMessage(String message) {
            this.message = message
        }
    }
}

@mockMessage
@parallel=true
Feature: Test Message

  Background:
    * url localUrl

  Scenario: GET

  Given path '/message'
  When method get
  Then status 200

  * print 'foo value ' + karate.properties['foo']
  * def getMessage =
    """
    function() {
      var MessageHolder = Java.type('com.example.spock.karate.ApiTestRunnerSpec.MessageHolder');
      return MessageHolder.INSTANCE.getMessage();
    }
    """
  * def message = call getMessage {}
  * print 'message value ' + message

Update 2: This is the implementation of Peter's second idea to simply access Java system properties via JS. So I simplified the working, but unnecessarily complicated version with the message holder singleton, eliminating it again:

https://github.com/kriegaex/spock-karate-example/commit/e235dd71

Now it simply looks like this (similar to the original Spock specification, only refactored to be a bit less verbose):

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class ApiTestRunnerSpec extends Specification {

    @LocalServerPort
    private int port

    @SpringBean
    MessageLogger messageLogger = Mock() {
        1 * logMessage(_ as String) >> { String message ->
            assert message != null
            System.setProperty('message', message)
        }
    }

    def "setup"() {
        System.out.println("Running on port: " + port)
        System.setProperty("server.port", "" + port)
    }

    def "Run Mock ApiTest"() {
        expect:
        Runner.path("classpath:").systemProperty("foo", "bar").tags("~@ignore").parallel(5)
    }
}

The only important change is in the Karate feature:

@mockMessage
@parallel=true
Feature: Test Message

  Background:
    * url localUrl

  Scenario: GET

  Given path '/message'
  When method get
  Then status 200

  * print 'foo value ' + karate.properties['foo']
  * def getMessage = function() { return Java.type('java.lang.System').getProperty('message'); }
  * print 'message value ' + getMessage()

The Runner "builder" has a .systemProperty() method which is recommended.

Please refer: https://github.com/intuit/karate/wiki/1.0-upgrade-guide#improved-test-suite-builder

So this should work. Else as I said in the comments, please submit a way to replicate.

Results results = Runner.path("classpath:")
    .systemProperty("foo", "bar")
    .tags("~@ignore").parallel(5)

EDIT: so I can confirm that karate.properties is made immutable at the time the test-suite starts.

So here are the 3 options:

• change your test strategy so that all dynamic params are resolved before you start
• instead of karate.properties[] do the old-school java.lang.System.getProperty('foo') call in Karate / JS, I'm pretty sure that will work
• use a Java singleton to hold shared state for your test-runner and karate-feature