How to run the tests in single thread

I’m writing a new dialect based on postgresql.
I see the tests are run in parallel when run like below.
./gradlew test -Pdb=pgsql
I need to run these test in serial order. Changing the flag org.gradle.parallel to false in did not help. Any idea how to make it work? Thanks

I don’t know why you think that tests are run in parallel, it’s only the Gradle tasks that run in parallel, but tests that use a database are ensured to run one test task after another.
Changing org.gradle.parallel in should work, though you can also pass a command line argument ./gradlew build --no-parallel. Also see Command-Line Interface