Add default_literal test

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 60.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 59.80%. Comparing base (1e98f67) to head (6f76375). Report is 5 commits behind head on master.

Files with missing lines	Patch %	Lines
tests/idl4/default_literal/client.cpp	60.00%	4 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #397 +/- ## ======================================= Coverage 59.80% 59.80% ======================================= Files 597 598 +1 Lines 47586 47601 +15 Branches 4214 4216 +2 ======================================= + Hits 28460 28470 +10 - Misses 16006 16010 +4 - Partials 3120 3121 +1 ```

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