withReuse between files

[botflux]

Hey, I'm using withReuse to re-use my containers between test runs, and it works fine when tests run serially in the same node process.
But, with test runners like node:test, each test file runs in a different node process, and it seems that the containers are not reused correctly in this case.

If I understand the code correctly, the reuse feature is based on a in-memory lock, so it makes sense that the feature doesn't work with parallel execution.

the lock's initialization

I've done a minimal reproduction here.

Expected Behaviour

Containers configured with .withReuse should be re-used, even when started from two different nodejs processes.

Actual Behaviour

Containers configured with .withReuse are not reused when the tests are running in different nodejs processes.
If two test files are defined, and each file starts the re-used container, then the container will be started twice.

Testcontainer Logs
...

Steps to Reproduce
The steps are in the reproduction repository

Environment Information

• Operating System: macOS Sequoia 15.6.1
• Docker Version: Docker version 28.3.2, build 578ccf6
• Node version: v24.10.0
• Testcontainers version: 11.7.2

[cristianrgreco]

Hey @botflux

I don't think the withReuse use case was really considered for a multi-process execution environment. If you want a single container to be shared amongst all tests you should probably be using the setupFiles equivalent of your test framework, e.g. https://node.testcontainers.org/quickstart/global-setup/

[botflux]

Thank for your answer @cristianrgreco

Ok, I understand, and I'll close it.
node:test has a global setup feature since Node v24.0.0 (docs), I'll use it.