Investigate flakey macro and script tests

[rmccar]

Summary
Our macro and script tests are not reliable in their performance. We need to investigate why this is happening and try to fix it so that they pass every time, unless something is actually broken.

Expected behaviour
Test outcome is true reflection of the issue. If the test failed it should not be correct on the second attempt without actioning any changes.

Actual behaviour
When we run tests on our GitHub actions, quite often there is one or two failures. When run again locally they all pass.

Screenshots/Examples

Here is an example of one of the tests that fails intermittently: