Use pytest.mark.parametrize instead of loops in host tests

[dannywillems]

Problem

`test_client.py` `test_get_host_success` and `test_get_host_404` iterate over fixture files in a loop. If the directory is empty, zero test cases pass silently. Each case should be a distinct test so failures are individually visible.

Solution

• Use `pytest.mark.parametrize` with fixture file paths
• Each file becomes a separate test case
• Empty directory = zero parametrized cases = visible in test output