feat: OTEL

tests/core/test_logging_config.py

@@ -0,0 +1,104 @@
+"""Tests for setup_logging — in particular the OTEL log-handler hand-off.
+
+`opentelemetry-instrument` attaches an OTEL `LoggingHandler` to the root
+logger before our module-level `setup_logging()` runs in `application/app.py`.
+The default `dictConfig` call replaces `root.handlers`, which would silently
+drop the OTEL handler. setup_logging snapshots and re-attaches OTEL handlers
+when OTLP log export is enabled.
+"""
+
+from __future__ import annotations
+
+import logging
+import sys
+import types
+
+import pytest
+
+from application.core.logging_config import setup_logging
+
+
+@pytest.fixture(autouse=True)
+def _reset_root_logger():
+    """Snapshot/restore the root logger so tests don't leak handlers."""
+    root = logging.getLogger()
+    saved_handlers = list(root.handlers)
+    saved_level = root.level
+    yield
+    root.handlers = saved_handlers
+    root.setLevel(saved_level)
+
+
+def _make_fake_otel_handler() -> logging.Handler:
+    """Build a Handler whose class lives in a module starting with 'opentelemetry'.
+
+    Mirrors how the real `opentelemetry.sdk._logs.LoggingHandler` would be
+    detected without needing the OTEL SDK installed in the test env.
+    """
+    fake_module = types.ModuleType("opentelemetry.fake_sdk._logs")
+    sys.modules.setdefault(fake_module.__name__, fake_module)
+
+    class FakeOtelHandler(logging.Handler):
+        pass
+
+    FakeOtelHandler.__module__ = fake_module.__name__
+    return FakeOtelHandler()
+
+
+@pytest.mark.unit
+class TestSetupLogging:
+
+    def test_default_keeps_only_console_handler(self, monkeypatch):
+        monkeypatch.delenv("OTEL_LOGS_EXPORTER", raising=False)
+        monkeypatch.delenv("OTEL_SDK_DISABLED", raising=False)
+        logging.getLogger().handlers = []
+
+        setup_logging()
+
+        handlers = logging.getLogger().handlers
+        assert len(handlers) == 1
+        assert isinstance(handlers[0], logging.StreamHandler)
+
+    def test_preserves_otel_handler_when_otlp_logs_enabled(self, monkeypatch):
+        monkeypatch.setenv("OTEL_LOGS_EXPORTER", "otlp")
+        monkeypatch.delenv("OTEL_SDK_DISABLED", raising=False)
+
+        otel_handler = _make_fake_otel_handler()
+        logging.getLogger().handlers = [otel_handler]
+
+        setup_logging()
+
+        handlers = logging.getLogger().handlers
+        assert otel_handler in handlers, (
+            "OTEL handler must survive setup_logging when OTLP log export is on"
+        )
+        assert any(
+            isinstance(h, logging.StreamHandler) and not isinstance(h, type(otel_handler))
+            for h in handlers
+        ), "console handler should still be installed alongside the OTEL handler"
+
+    def test_does_not_preserve_when_sdk_disabled(self, monkeypatch):
+        monkeypatch.setenv("OTEL_LOGS_EXPORTER", "otlp")
+        monkeypatch.setenv("OTEL_SDK_DISABLED", "true")
+
+        otel_handler = _make_fake_otel_handler()
+        logging.getLogger().handlers = [otel_handler]
+
+        setup_logging()
+
+        handlers = logging.getLogger().handlers
+        assert otel_handler not in handlers, (
+            "When OTEL_SDK_DISABLED=true the handler should not be preserved"
+        )
+
+    def test_does_not_preserve_when_logs_exporter_unset(self, monkeypatch):
+        monkeypatch.delenv("OTEL_LOGS_EXPORTER", raising=False)
+        monkeypatch.delenv("OTEL_SDK_DISABLED", raising=False)
+
+        otel_handler = _make_fake_otel_handler()
+        logging.getLogger().handlers = [otel_handler]
+
+        setup_logging()
+
+        handlers = logging.getLogger().handlers
+        assert otel_handler not in handlers