Jenkins-test-harness - JenkinsRule - how to provide credentials for the test run

Using Jenkins
1

Hi,

I am using jenkins-test-harness to test my DSL scripts (Testing DSL Scripts · jenkinsci/job-dsl-plugin Wiki · GitHub).

That works very well so far but I still have an open question.

Some of those DSL scripts do install a ScmSource with a credential definition:

		branchSources {
			branchSource {
				source {
					bitbucket {
						credentialsId('bitbucket-token')

How can I provide those credentials (credentialsId(…) from above) in my spock test setup?

I had a look on the JenkinsRule but did not find something obvious to provide them, Hints are appreciated. Thanks.