testpim.py must use valgrind in the nightly testing. There have been leaks in some of the code which valgrind can report. Example:

==17726== 64 bytes in 2 blocks are definitely lost in loss record 4,109 of 6,887
==17726==    at 0x4C28BED: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==17726==    by 0xDB95D50: g_malloc (gmem.c:159)
==17726==    by 0xDBAAC92: g_slice_alloc (gslice.c:1003)
==17726==    by 0xDBAB1E5: g_slice_alloc0 (gslice.c:1029)
==17726==    by 0xDB79B6A: g_date_time_alloc (gdatetime.c:432)
==17726==    by 0xDB79CE2: g_date_time_from_instant (gdatetime.c:528)
==17726==    by 0xDB7C3D3: g_date_time_to_utc (gdatetime.c:2077)
==17726==    by 0x11235C9: SyncEvo::DBus2PersonaDetails(GDBusCXX::ExtractArgs&, _GVariantIter&, SyncEvo::PersonaDetails&) (individual-traits.cpp:607)

            g_hash_table_insert(details.get(),
                                const_cast<gchar *>(folks_persona_store_detail_key(FOLKS_PERSONA_DETAIL_BIRTHDAY)),
                                new GValueDateTimeCXX(g_date_time_to_utc(local.get())));
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
returns an instance which is copied by GValueDateTimeCXX instead of taking ownership.