[foreign-memaccess+abi] RFR: Add exhaustive test for resource scope handle

[Chris Hegarty]

On Wed, 14 Apr 2021 16:06:02 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

> During some recent benchmarking, we have identified an issue where acquiring/closing a scope handle on an implicit scope was not working as expected, and was throwing an NPE instead.
> This patch adds a test which acquires 5 handles (recursively), and then release them.
> It checks all the different scope variants, and, for each acquired handle it also tests for idempotency.

LGTM.

Trivially you could replace the try-catch-or-fail with
   assertThrows(IllegalStateException.class, scope::close);

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Marked as reviewed by chegar (Committer).

PR: https://git.openjdk.java.net/panama-foreign/pull/504