circleci with parallelism - each container executing all the tests - gradle

Question

I want my integration tests to run in parallel on Circleci.
I read this document https://circleci.com/blog/how-to-boost-build-time-with-test-parallelism/ and I setup my job like this
platform_component_test:
working_directory: *workspace_root
executor: ubuntu-machine
parallelism: 16
steps:
- prepare_workspace
- run:
name: 'Run Platform Component tests'
command:
./gradlew platform:componentTest -PtestFilter="`circleci tests glob "platform/src/componentTest/java/**/*.java"|circleci tests split`"
By looking at the UI, I see that each of the 16 containers that are spawn execute all the tests.
Am I missing something?

Answer 1

I ended up slightly modifying this and incorporating what I learned from here and here to build this:
- run:
name: Run tests in parallel
# Use "./gradlew test" instead if tests are not run in parallel
command: |
cd module-with-tests-to-run/src/test/kotlin
# Get list of classnames of tests that should run on this node
CLASSNAMES=$(circleci tests glob "**/**Test.kt" \
| cut -c 1- | sed 's#/#.#g' \
| sed 's/.\{3\}$//' \
| circleci tests split --split-by=timings --timings-type=classname)
cd ../../../..
# Format the arguments to "./gradlew test"
GRADLE_ARGS=$(echo $CLASSNAMES | awk '{for (i=1; i<=NF; i++) print "--tests",$i}')
echo "Prepared arguments for Gradle: $GRADLE_ARGS"
./gradlew clean module-with-tests-to-run:test $GRADLE_ARGS
note: I tried to get the formatting right but I might have goofed.