Problem
All 6 tests in test/telemetry/test_tracing_backend.py always skip with reason Telemetry not initialized, even when OTel is installed and Ollama is running.
Found whilst working on PR #742. Flagging for @ajbozart as the original author of the telemetry tests.
Root Cause
mellea/telemetry/tracing.py sets _tracer_provider at module import time based on the MELLEA_TRACE_BACKEND env var:
_tracer_provider = None
if _OTEL_AVAILABLE and (_TRACE_APPLICATION_ENABLED or _TRACE_BACKEND_ENABLED):
_tracer_provider = _setup_tracer_provider()The test's setup_telemetry fixture uses MonkeyPatch.setenv("MELLEA_TRACE_BACKEND", "true"), but by the time the fixture runs, tracing.py is already imported and _tracer_provider is already None. setenv cannot retroactively change a module-level constant.
The span_exporter fixture then checks if provider is None: pytest.skip(...) — which always fires.
Attempted Fix
Patching tracing._backend_tracer and tracing._TRACE_BACKEND_ENABLED directly in the fixture (bypassing the env var) gets 4/6 tests passing. The remaining 2 have deeper design issues:
test_span_duration_captures_async_operation: calls trace.get_tracer_provider().force_flush() on the global OTel provider, not the test provider — flushes the wrong thing. Span name search for "chat" may also not match.test_context_propagation_parent_child: creates its parent span via trace.get_tracer(__name__) (global provider) but backend spans go to the test provider. Parent span never reaches InMemorySpanExporter. Context propagation assertion requires both spans on the same provider.
Suggested Fix
In span_exporter fixture, directly patch the module internals rather than relying on env var:
@pytest.fixture
def span_exporter():
from mellea.telemetry import tracing
provider = TracerProvider()
exporter = InMemorySpanExporter()
provider.add_span_processor(SimpleSpanProcessor(exporter))
test_tracer = provider.get_tracer("mellea.backend")
old_tracer = tracing._backend_tracer
old_enabled = tracing._TRACE_BACKEND_ENABLED
tracing._backend_tracer = test_tracer
tracing._TRACE_BACKEND_ENABLED = True
yield exporter
exporter.clear()
tracing._backend_tracer = old_tracer
tracing._TRACE_BACKEND_ENABLED = old_enabledtest_context_propagation_parent_child additionally needs to create its parent span using the test tracer (not trace.get_tracer(__name__)) so both spans land on the same provider.
Verification
With the partial fix above, 4/6 tests pass against a live Ollama instance. The 2 remaining failures require the test bodies to be updated.
Problem
All 6 tests in
test/telemetry/test_tracing_backend.pyalways skip with reasonTelemetry not initialized, even when OTel is installed and Ollama is running.Found whilst working on PR #742. Flagging for @ajbozart as the original author of the telemetry tests.
Root Cause
mellea/telemetry/tracing.pysets_tracer_providerat module import time based on theMELLEA_TRACE_BACKENDenv var:The test's
setup_telemetryfixture usesMonkeyPatch.setenv("MELLEA_TRACE_BACKEND", "true"), but by the time the fixture runs,tracing.pyis already imported and_tracer_provideris alreadyNone.setenvcannot retroactively change a module-level constant.The
span_exporterfixture then checksif provider is None: pytest.skip(...)— which always fires.Attempted Fix
Patching
tracing._backend_tracerandtracing._TRACE_BACKEND_ENABLEDdirectly in the fixture (bypassing the env var) gets 4/6 tests passing. The remaining 2 have deeper design issues:test_span_duration_captures_async_operation: callstrace.get_tracer_provider().force_flush()on the global OTel provider, not the test provider — flushes the wrong thing. Span name search for"chat"may also not match.test_context_propagation_parent_child: creates its parent span viatrace.get_tracer(__name__)(global provider) but backend spans go to the test provider. Parent span never reachesInMemorySpanExporter. Context propagation assertion requires both spans on the same provider.Suggested Fix
In
span_exporterfixture, directly patch the module internals rather than relying on env var:test_context_propagation_parent_childadditionally needs to create its parent span using the test tracer (nottrace.get_tracer(__name__)) so both spans land on the same provider.Verification
With the partial fix above, 4/6 tests pass against a live Ollama instance. The 2 remaining failures require the test bodies to be updated.