Test dependencies leaked into project.getConfigurations().detachedConfiguration(deps)

Here is a snippet of code from my Gradle plugin:

    final Configuration deploymentConfig = project.getConfigurations()
            .detachedConfiguration(extensionDeps.toArray(new Dependency[0]));
    final ResolvedConfiguration rc = deploymentConfig.getResolvedConfiguration();
    for (ResolvedArtifact a : rc.getResolvedArtifacts()) {

When I use the plugin in an application, I see that there are test dependencies among the resolved artifacts, although extensionDeps don’t include those and don’t depend (at least not at compile time) on them.
My question is whether is this an expected outcome or possibly an issue in the dependency resolver in Gradle itself? Thanks.