Tests are not deterministic

[Diggsey]

Problem Description

Many of the existing tests execute a SELECT query without an ORDER BY clause, and then compare the results against a list of expected rows. At least for postgres, the order of rows returned is not defined, so the tests will sometimes fail.

What is the expected output?

The tests should use an unordered comparison, eg. by putting the results in a BTreeSet before comparing them, or should use an ORDER BY clause on any SELECT queries.

Steps to reproduce

Unclear: running the tests for the first time on a brand new database caused it for me. Rerunning the tests resulted in the result order stabilising, and the tests passed after that.

Checklist

• I have already looked over the issue tracker for similar issues.