Fix traceback construction in tests using threadpool

examples/test_example_fail_in_thread.py

@@ -0,0 +1,21 @@
+from concurrent.futures.thread import ThreadPoolExecutor
+from threading import Thread
+
+
+import pytest_check as check
+
+
+def force_fail(comparison):
+    check.equal(1 + 1, comparison, f"1 + 1 is 2, not {comparison}")
+
+
+def test_threadpool():
+    with ThreadPoolExecutor() as executor:
+        task = executor.submit(force_fail, 3)
+        task.result()
+
+
+def test_threading():
+    t = Thread(target=force_fail, args=(4, ))
+    t.start()
+    t.join()

examples/test_example_pass_in_thread.py

@@ -0,0 +1,21 @@
+from concurrent.futures.thread import ThreadPoolExecutor
+from threading import Thread
+
+
+import pytest_check as check
+
+
+def always_pass():
+    check.equal(1 + 1, 2)
+
+
+def test_threadpool():
+    with ThreadPoolExecutor() as executor:
+        task = executor.submit(always_pass)
+        task.result()
+
+
+def test_threading():
+    t = Thread(target=always_pass)
+    t.start()
+    t.join()

src/pytest_check/pseudo_traceback.py

@@ -4,8 +4,8 @@
 _traceback_style = "auto"
 
 
-def get_full_context(level):
-    (_, filename, line, funcname, contextlist) = inspect.stack()[level][0:5]
+def get_full_context(frame):
+    (_, filename, line, funcname, contextlist) = frame[0:5]
     try:
         filename = os.path.relpath(filename)
     except ValueError:  # pragma: no cover
@@ -28,11 +28,12 @@ def _build_pseudo_trace_str():
     if _traceback_style == "no":
         return ""
 
-    level = 4
+    skip_own_frames = 3
     pseudo_trace = []
     func = ""
-    while "test_" not in func:
-        (file, line, func, context) = get_full_context(level)
+    context_stack = inspect.stack()[skip_own_frames:]
+    while "test_" not in func and context_stack:
+        (file, line, func, context) = get_full_context(context_stack.pop(0))
         # we want to trace through user code, not 3rd party or builtin libs
         if "site-packages" in file:
             break
@@ -41,6 +42,5 @@ def _build_pseudo_trace_str():
             break
         line = f"{file}:{line} in {func}() -> {context}"
         pseudo_trace.append(line)
-        level += 1
 
     return "\n".join(reversed(pseudo_trace)) + "\n"

tests/test_thread.py

@@ -0,0 +1,12 @@
+def test_failing_threaded_testcode(pytester):
+    pytester.copy_example("examples/test_example_fail_in_thread.py")
+    result = pytester.runpytest()
+    result.assert_outcomes(failed=2, passed=0)
+    result.stdout.fnmatch_lines(["*1 + 1 is 2, not 3*"])
+    result.stdout.fnmatch_lines(["*1 + 1 is 2, not 4*"])
+
+
+def test_passing_threaded_testcode(pytester):
+    pytester.copy_example("examples/test_example_pass_in_thread.py")
+    result = pytester.runpytest()
+    result.assert_outcomes(failed=0, passed=2)