diff --git a/src/main/groovy/org/jenkinsci/gradle/plugins/jpi/JpiPlugin.groovy b/src/main/groovy/org/jenkinsci/gradle/plugins/jpi/JpiPlugin.groovy
index eb73ce46..976dbad2 100644
--- a/src/main/groovy/org/jenkinsci/gradle/plugins/jpi/JpiPlugin.groovy
+++ b/src/main/groovy/org/jenkinsci/gradle/plugins/jpi/JpiPlugin.groovy
@@ -422,10 +422,13 @@ class JpiPlugin implements Plugin<Project> {
 
         // generate test hpl manifest for the current plugin, to be used during unit test
         def outputDir = project.layout.buildDirectory.dir('generated-resources/test')
-        project.tasks.register('generate-test-hpl', GenerateTestHpl) {
+        testSourceSet.output.dir(outputDir)
+
+        def generateTestHplTask = project.tasks.register('generate-test-hpl', GenerateTestHpl) {
             it.hplDir.set(outputDir)
         }
-        testSourceSet.output.dir(outputDir)
+
+        project.tasks.named(JavaPlugin.TEST_CLASSES_TASK_NAME).configure { it.dependsOn(generateTestHplTask) }
     }
 
     private static void resolvePluginDependencies(Project project) {
diff --git a/src/test/groovy/org/jenkinsci/gradle/plugins/jpi/JpiIntegrationSpec.groovy b/src/test/groovy/org/jenkinsci/gradle/plugins/jpi/JpiIntegrationSpec.groovy
index aca70047..b62c85a9 100644
--- a/src/test/groovy/org/jenkinsci/gradle/plugins/jpi/JpiIntegrationSpec.groovy
+++ b/src/test/groovy/org/jenkinsci/gradle/plugins/jpi/JpiIntegrationSpec.groovy
@@ -166,6 +166,7 @@ class JpiIntegrationSpec extends IntegrationSpec {
         'processTestResources' | ':resolveTestDependencies' | TaskOutcome.NO_SOURCE
         'jpi'                  | ':war'                     | TaskOutcome.SUCCESS
         'compileTestJava'      | ':insertTest'              | TaskOutcome.SKIPPED
+        'testClasses'          | ':generate-test-hpl'       | TaskOutcome.SUCCESS
         'compileJava'          | ':localizer'               | TaskOutcome.SUCCESS
     }