diff --git a/launchable/test_runners/pytest.py b/launchable/test_runners/pytest.py
index 2919767f0..3ecbbd94d 100644
--- a/launchable/test_runners/pytest.py
+++ b/launchable/test_runners/pytest.py
@@ -264,27 +264,41 @@ def parse_func(
                 stderr = ""
                 longrepr = data.get("longrepr", None)
                 if longrepr:
-                    message = None
-                    reprcrash = longrepr.get("reprcrash", None)
-                    if reprcrash:
-                        message = reprcrash.get("message", None)
-
-                    text = None
-                    reprtraceback = longrepr.get("reprtraceback", None)
-                    if reprtraceback:
-                        reprentries = reprtraceback.get("reprentries", None)
-                        if reprentries:
-                            for r in reprentries:
-                                d = r.get("data", None)
-                                if d:
-                                    text = "\n".join(d.get("lines", []))
-
-                    if message and text:
-                        stderr = message + "\n" + text
-                    elif message:
-                        stderr = stderr + message
-                    elif text:
-                        stderr = stderr + text
+                    # https://github.com/pytest-dev/pytest/blob/1d7d63555e431d4562bcacbdc97038b0613d20ba/src/_pytest/reports.py#L60
+                    if isinstance(longrepr, dict):
+                        # https://github.com/pytest-dev/pytest/blob/1d7d63555e431d4562bcacbdc97038b0613d20ba/src/_pytest/reports.py#L361
+                        message = None
+                        reprcrash = longrepr.get("reprcrash", None)
+                        if reprcrash:
+                            message = reprcrash.get("message", None)
+
+                        text = None
+                        reprtraceback = longrepr.get("reprtraceback", None)
+                        if reprtraceback:
+                            reprentries = reprtraceback.get("reprentries", None)
+                            if reprentries:
+                                for r in reprentries:
+                                    d = r.get("data", None)
+                                    if d:
+                                        text = "\n".join(d.get("lines", []))
+
+                        if message and text:
+                            stderr = message + "\n" + text
+                        elif message:
+                            stderr = stderr + message
+                        elif text:
+                            stderr = stderr + text
+                    elif isinstance(longrepr, list):
+                        # [path, lineno, messge]
+                        # https://github.com/pytest-dev/pytest/blob/1d7d63555e431d4562bcacbdc97038b0613d20ba/src/_pytest/reports.py#L371
+                        if len(longrepr) == 3:
+                            stderr = longrepr[2]
+
+                    elif isinstance(longrepr, str):
+                        # When longrepr is a string, it is the same as the stderr.
+                        # https://github.com/pytest-dev/pytest/blob/1d7d63555e431d4562bcacbdc97038b0613d20ba/src/_pytest/reports.py#L377
+                        # https://github.com/pytest-dev/pytest/blob/1d7d63555e431d4562bcacbdc97038b0613d20ba/src/_pytest/nodes.py#L470
+                        stderr = longrepr
 
                 test_path = _parse_pytest_nodeid(nodeid)
                 for path in test_path:
diff --git a/tests/test_runners/test_pytest.py b/tests/test_runners/test_pytest.py
index 092fd3f31..5cfe90790 100644
--- a/tests/test_runners/test_pytest.py
+++ b/tests/test_runners/test_pytest.py
@@ -1,11 +1,12 @@
 import gzip
 import json
 import os
-from unittest import mock
+import tempfile
+from unittest import TestCase, mock
 
 import responses  # type: ignore
 
-from launchable.test_runners.pytest import _parse_pytest_nodeid
+from launchable.test_runners.pytest import PytestJSONReportParser, _parse_pytest_nodeid
 from tests.cli_test_case import CliTestCase
 
 
@@ -77,3 +78,63 @@ def test_parse_pytest_nodeid(self):
             {"type": "class", "name": "tests.fooo.func4_test"},
             {"type": "testcase", "name": "test_func6"},
         ])
+
+
+class PytestJSONReportParserLongreprTest(TestCase):
+    class DummyClient:
+        pass
+
+    def setUp(self):
+        self.parser = PytestJSONReportParser(self.DummyClient())
+
+    def _parse_line(self, data):
+        with tempfile.NamedTemporaryFile(mode="w+", delete=False) as f:
+            f.write(json.dumps(data) + "\n")
+            f.flush()
+            results = list(self.parser.parse_func(f.name))
+        return results
+
+    def _make_event_data(self, longrepr):
+        return {
+            "nodeid": "tests/test_sample.py::test_fail",
+            "when": "call",
+            "outcome": "failed",
+            "longrepr": longrepr,
+        }
+
+    def _assert_stderr(self, events, expected_stderr):
+        self.assertEqual(events[0]["stderr"], expected_stderr)
+
+    def test_longrepr_dict_message_and_text(self):
+        data = self._make_event_data(
+            {
+                "reprcrash": {"message": "AssertionError: fail"},
+                "reprtraceback": {
+                    "reprentries": [{"data": {"lines": ["line1", "line2"]}}]
+                },
+            }
+        )
+        events = self._parse_line(data)
+        self._assert_stderr(events, "AssertionError: fail\nline1\nline2")
+
+    def test_longrepr_dict_only_message(self):
+        data = self._make_event_data({"reprcrash": {"message": "Only message"}})
+        events = self._parse_line(data)
+        self._assert_stderr(events, "Only message")
+
+    def test_longrepr_dict_only_text(self):
+        data = self._make_event_data(
+            {"reprtraceback": {"reprentries": [{"data": {"lines": ["text only"]}}]}}
+        )
+        events = self._parse_line(data)
+        self._assert_stderr(events, "text only")
+
+    def test_longrepr_list(self):
+        data = self._make_event_data(["file.py", 10, "list message"])
+        events = self._parse_line(data)
+        self._assert_stderr(events, "list message")
+
+    def test_longrepr_str(self):
+        data = self._make_event_data("string message")
+        events = self._parse_line(data)
+        self._assert_stderr(events, "string message")