fix(langfuse): replace MagicMock with Mock to prevent RAM exhaustion (#2543)

[GunaPalanivel]

• Fixes bug(langfuse): test_create_new_span causes excessive RAM usage and hangs due to unspecced MagicMock #2543

• test hangs on Linux Python 3.9/3.13 due to unspecced MagicMock().

Changes

Replaced MagicMock() with Mock() on lines 571 and 589 in test_tracer.py.

Unspecced MagicMock creates infinite child mocks on attribute access, which caused handle() to hang while iterating mock objects. A partial workaround existed (get_data.return_value = {}), but the root mocks were still unspecced.

Testing

• test_create_new_span passes
• All other tracer tests pass (32 total)

Note

Two pre-existing failures (test_set_content_tag_updates_input_and_output*) exist on main and are unrelated; should be tracked separately.

[GunaPalanivel]

If maintainers prefer a stricter approach, I can switch to:

mock_raw_span = Mock(spec=["operation_name", "metadata", "update", "raw_span"])

The current Mock() change is sufficient for this fix.