DOC: Explain why tests are commented out.

tests/test_autotap.sql

@@ -38,6 +38,10 @@ SELECT tap.has_schema('_caosdb_schema_unit_tests','');
 -- ***************************************************************
 
 SELECT tap.has_table('_caosdb_schema_unit_tests','archive_isa','');
+-- *******
+-- Collation testing of tables fails for uca1400 collations, see upstream issue:
+-- https://github.com/hepabolu/mytap/issues/58
+-- *******
 -- SELECT tap.table_collation_is('_caosdb_schema_unit_tests','archive_isa','utf8mb4_uca1400_as_ci','');
 SELECT tap.table_engine_is('_caosdb_schema_unit_tests','archive_isa','InnoDB','');