RFR: 8285295: Need better testing for IdentityHashMap

[liach]

On Fri, 22 Apr 2022 03:37:27 GMT, Stuart Marks <smarks at openjdk.org> wrote:

> Basic but fairly comprehensive set of tests for `IdentityHashMap`. The patch in the bug report that breaks `IdentityHashMap` now causes several cases in this new test to fail. There's more that could be done, but the new tests cover most of the core functions of `IdentityHashMap`. Unfortunately it seems difficult to merge this with the existing, comprehensive Collections tests (e.g., MOAT.java) because those tests implicity rely on `equals()`-based contract instead of the special-purpose `==`-based contract used by `IdentityHashMap`.

Just curious, will entrySet/keySet/values tests be here or in a separate file? They are identity-based collections as well, as shown by their contains/removeAll/retainAll.

test/jdk/java/util/IdentityHashMap/Basic.java line 75:

> 73:     private <E> void checkContents(Collection<E> c, BiPredicate<E,E> p, E... given) {
> 74:         @SuppressWarnings("unchecked")
> 75:         E[] contents = (E[]) c.toArray();

Maybe worthy to note that entry set toArray may return entries different from what the iterator returns, and some predicates may thus fail.

test/jdk/java/util/IdentityHashMap/Basic.java line 77:

> 75:         E[] contents = (E[]) c.toArray();
> 76: 
> 77:         assertEquals(c.size(), given.length);

I believe testng has the expected values in front in the `assertEquals` methods, as embodied in the exception messages, so this should be `assertEquals(given.length, c.size());`. Applies to other places.

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PR: https://git.openjdk.java.net/jdk/pull/8354