From 44b6e410b4abf256bc31f831e5c77b62072a8938 Mon Sep 17 00:00:00 2001
From: Alex Suraci <suraci.alex@gmail.com>
Date: Wed, 13 May 2026 20:41:25 -0400
Subject: [PATCH] fix: log test errors on spans

Keep failed test span statuses low-cardinality while emitting assertion details
as stderr logs. This preserves failure details in UIs without stuffing dynamic
output into span status descriptions.

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>
---
 pytest_otel/src/pytest_otel/tracer.py |  4 +--
 pytest_otel/tests/test_plugin.py      | 27 ++++++++++++++++
 pytest_otel/tests/test_tracer.py      | 46 ++++++++++++++++++++++++++-
 3 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/pytest_otel/src/pytest_otel/tracer.py b/pytest_otel/src/pytest_otel/tracer.py
index 3a9b4b0..3cf2800 100644
--- a/pytest_otel/src/pytest_otel/tracer.py
+++ b/pytest_otel/src/pytest_otel/tracer.py
@@ -109,7 +109,7 @@ def end_session(self, exitstatus: int) -> None:
         if exitstatus == 0:
             span.set_status(Status(StatusCode.OK))
         else:
-            span.set_status(Status(StatusCode.ERROR, f"Exit status: {exitstatus}"))
+            span.set_status(Status(StatusCode.ERROR, "test session failed"))
 
         span.end()
 
@@ -178,7 +178,7 @@ def end_test(self, item: "pytest.Item", outcome: str) -> None:
         if outcome == "passed":
             span.set_status(Status(StatusCode.OK))
         elif outcome in ("failed", "error"):
-            span.set_status(Status(StatusCode.ERROR, f"Test {outcome}"))
+            span.set_status(Status(StatusCode.ERROR, "test failed"))
         # "skipped" keeps UNSET status (neither OK nor ERROR)
 
         span.end()
diff --git a/pytest_otel/tests/test_plugin.py b/pytest_otel/tests/test_plugin.py
index b6f26fd..44155c4 100644
--- a/pytest_otel/tests/test_plugin.py
+++ b/pytest_otel/tests/test_plugin.py
@@ -115,3 +115,30 @@ def test_capture_stderr(self, monkeypatch):
         plugin._capture_test_output(mock_item, report)
 
         assert emitted == [("test stderr", STDIO_STREAM_STDERR, mock_span)]
+
+    def test_capture_failure_details(self, monkeypatch):
+        """Test that assertion details are captured as stderr logs."""
+        from pytest_otel import plugin
+        from pytest_otel.logging_handler import STDIO_STREAM_STDERR
+
+        mock_item = Mock()
+        mock_item.nodeid = "tests/test_example.py::test_function"
+        mock_span = Mock()
+        emitted = []
+
+        monkeypatch.setattr(plugin.tracer, "get_test_span", lambda item: mock_span)
+        monkeypatch.setattr(
+            "pytest_otel.logging_handler.emit_stdio_log",
+            lambda body, stream, span=None: emitted.append((body, stream, span)),
+        )
+
+        report = Mock()
+        report.when = "call"
+        report.failed = True
+        report.capstdout = None
+        report.capstderr = None
+        report.longrepr = "assert 1 == 2"
+
+        plugin._capture_test_output(mock_item, report)
+
+        assert emitted == [("assert 1 == 2", STDIO_STREAM_STDERR, mock_span)]
diff --git a/pytest_otel/tests/test_tracer.py b/pytest_otel/tests/test_tracer.py
index 9aed115..232efbd 100644
--- a/pytest_otel/tests/test_tracer.py
+++ b/pytest_otel/tests/test_tracer.py
@@ -1,6 +1,10 @@
 """Tests for the tracer module."""
 
-from pytest_otel.tracer import SpanContextManager
+from unittest.mock import Mock
+
+from opentelemetry.trace import StatusCode
+
+from pytest_otel.tracer import SpanContextManager, TestNode as OtelTestNode
 
 
 class TestParseNodeid:
@@ -84,6 +88,46 @@ def test_suite_run_status_mapping(self):
         assert ctx._suite_run_status(5) == TestSuiteRunStatusValues.SKIPPED.value
 
 
+class TestStatusDescriptions:
+    """Tests for low-cardinality span status descriptions."""
+
+    def test_session_failure_status_is_static(self):
+        """Verify session failures do not include dynamic exit status text."""
+        ctx = SpanContextManager()
+        span = Mock()
+        ctx._session_node = OtelTestNode(
+            nodeid="session",
+            name="pytest session",
+            kind="session",
+            span=span,
+        )
+
+        ctx.end_session(1)
+
+        status = span.set_status.call_args.args[0]
+        assert status.status_code == StatusCode.ERROR
+        assert status.description == "test session failed"
+
+    def test_test_failure_status_is_static(self):
+        """Verify test failures do not include dynamic assertion text."""
+        ctx = SpanContextManager()
+        span = Mock()
+        item = Mock()
+        item.nodeid = "tests/test_foo.py::test_bar"
+        ctx._tests[item.nodeid] = OtelTestNode(
+            nodeid=item.nodeid,
+            name="test_bar",
+            kind="function",
+            span=span,
+        )
+
+        ctx.end_test(item, "failed")
+
+        status = span.set_status.call_args.args[0]
+        assert status.status_code == StatusCode.ERROR
+        assert status.description == "test failed"
+
+
 class TestAttributeNames:
     """Tests for attribute name constants."""