The `test_rend_cache_purge` function contains an assertion which verifies that the internal strmap does not change after a purge (`src/test/test_rendcache.c:1044` on 0a701e537778ac9da31049f4efebf7cb2bf9c285). However, the `rend_cache_purge` function frees the internal strmap and allocates a new one. This turns the assertion in a check whether memory allocation returns the same address as was just freed. The C11 standard mentions that a previous call to `free` is synchronized with a call to `malloc` [0]. I found the issue during a Valgrind run which probably changed the behavior of `free` and `malloc` to track them and caused the assertion to fail. I am suggesting to remove the assertion because it verifies behavior that does not affect normal operation and (in my case) interferes with testing. [0] [http://en.cppreference.com/w/c/memory/malloc]