test_tiered06 exercises the WiredTiger storage source API - specifically ss_customize_file_system and file_system.terminate - against tiered storage backends including dir_store. It is currently suppressed in test/suite/fail_lists/asan.fail because it triggers LeakSanitizer errors under the ASan build.

Direct leak of 128 byte(s) in 1 object(s) allocated from:
    #2 __wt_storage_source__ss_customize_file_system wiredtigerPYTHON_wrap.c:3583
    #3 _wrap_StorageSource_ss_customize_file_system   wiredtigerPYTHON_wrap.c:11760

There are two independent sources of leakage:

1. A straightforward test oversight in test_ss_write_read: a file system is created but never explicitly terminated before the test exits.

2. A more fundamental issue exposed by test_ss_file_systems: the test deliberately verifies an API contract - that ss.terminate() is safe to call even when some customized file systems are still open, and that the storage source should clean up any remaining file systems on its own. The dir_store implementation does not honour this contract. Unlike the azure_store and gcp_store backends, dir_store does not track the file systems it creates and therefore cannot free them when the storage source is terminated. File systems that were not explicitly terminated by the caller are leaked.