fix java.lang.reflect.InaccessibleObjectException

caused by Mockito

ref: https://stackoverflow.com/questions/68113065/mockito-inaccessible-object-exception-while-creating-a-mock-object

To quote:
"This can happen if Mockito requires reflective access to non-public parts in a Java module.
you can get around this by explicitly allowing access via --add-opens in your java call"

build.gradle

@@ -129,6 +129,8 @@ compileJava {
 }
 
 test {
+    jvmArgs '--add-opens=java.base/java.util.concurrent=ALL-UNNAMED'
+
     testLogging {
         exceptionFormat "full"
         events "skipped", "passed", "failed", "started"