Produce more detailed diagnostics from failing test conditions

[jbardin]

Terraform Version

v1.6

Use Cases

The run condition expressions used in tests are going to primarily rely on equality for comparisons, and usually only between 2 values. When the values consist of complex types, the error diagnostics attempt to simplify the output by summarizing the references in the expression, like is object with 4 attributes, or is tuple with 3 elements. This summary doesn't usually help in the context of a test failure, since the types should be known, and the user is concerned with why the exact values in the expression aren't matching.

Attempted Solutions

It is possible to break down the expression into multiple assertions, but it would be convenient to enable direct comparison of more complex objects.

Proposal

Extend the diagnostic format for test failures, which can print complete values or even create smart diffs based on those values in the UI.

References

#34425

[albertorm95]

This will be very useful, I just face this scenario it was very hard to know what the issue was :(

[alex-harvey-z3q]

As I noted in the issue I just raised and closed as a duplicate, something similar to Python's pytest output is what is needed:

% pytest -vv test.py
...
    def test():
>       assert data == some_other
E       AssertionError: assert {'some': {'complex': 'data'}} == {'some_other': {'complex': 'data'}}
E         
E         Left contains 1 more item:
E         {'some': {'complex': 'data'}}
E         Right contains 1 more item:
E         {'some_other': {'complex': 'data'}}
E         
E         Full diff:
E           {
E         -     'some_other': {
E         ?          ------
E         +     'some': {
E                   'complex': 'data',
E               },
E           }

test.py:14: AssertionError

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