>>> +
>>> +-- Collation is set in space format and also in position() -
>>> +-- for both arguments. Arguments have different explicit
>>> +-- collations thus an error is expected.
>>> +
>>> +test:do_catchsql_test(
>>> +    "position-1.75",
>>> +    [[
>>> +        CREATE TABLE test1 (s1 VARCHAR(5) PRIMARY KEY COLLATE "unicode_ci");
>>> +        INSERT INTO test1 VALUES('à');
>>> +        SELECT POSITION('a' COLLATE "unicode_ci", s1 COLLATE "unicode") FROM test1;
>>> +    ]], {
>>> +        1, "Illegal mix of collations"
>>> +    }
>>> +)
>>> +
>>> +test:do_catchsql_test(
>>> +    "position-1.76",
>>> +    [[
>>> +        DROP TABLE test1;
>>> +        CREATE TABLE test1 (s1 VARCHAR(5) PRIMARY KEY COLLATE "unicode_ci");
>>> +        INSERT INTO test1 VALUES('qwèrty');
>>> +        SELECT POSITION('er' COLLATE "unicode_ci", s1 COLLATE "unicode") FROM test1;
>>> +        DROP TABLE test1;
>>> +    ]], {
>>> +        1, "Illegal mix of collations"
>>> +    }
>>> +)
>>> +
>>> +test:do_catchsql_test(
>>> +    "position-1.77",
>>> +    [[
>>> +        DROP TABLE test1;
>>> +        CREATE TABLE test1 (s1 VARCHAR(5) PRIMARY KEY COLLATE "unicode_ci");
>>> +        INSERT INTO test1 VALUES('qwèrtÿ');
>>> +        SELECT POSITION('Y' COLLATE "unicode_ci", s1 COLLATE "unicode") FROM test1;
>>> +    ]], {
>>> +        1, "Illegal mix of collations"
>>> +    }
>>> +)
>> 
>> Add test cases on: explicitly set incompatible collations,
>> explicitly set compatible collations.
>> 
>> 
> 
> Don’t we already have such tests? From the end of position.test.lua:
> 
> -- Collation is set in space format and also in position() -
> -- for both arguments. Arguments have the same collations.

Oh, I meant ‘implicitly set’. Still can’t find such tests.