Code coverage is not collected when writing tests as per the new Gradle 2.6 testing framework. Have I missed something?
At the moment the TestKit does not provide any automatic integration with the Jacoco plugin to generate code coverage metrics. You have a good point. Integration with the Jacoco plugin should be desirable. I am going to add it to the design spec for reference.
Keep in mind that the tests are executed in a Gradle daemon JVM which is different from the JVM initiating the test execution. In case you are executing the tests from an IDE, code coverage metrics cannot be collected as the tests run in a different JVM. Is that your use case or are you talking about the integration with the Jacoco plugin?
I do not use an IDE. This is simply by using Gradle on the command line, with the new test kit, and with Spock. I find the new test kit methodology awesome by the way!