Small refactoring based on feedback from @jdreaver

Author: nicoddemus

pytestqt/_tests/test_exceptions.py

@@ -1,4 +1,7 @@
+import textwrap
 import pytest
+import sys
+from pytestqt.plugin import capture_exceptions, format_captured_exceptions
 from pytestqt.qt_compat import QtGui, Qt, QtCore
 
 
@@ -32,3 +35,14 @@ def test_catch_exceptions_in_virtual_methods(qtbot, raise_error):
     app.processEvents()
 
 
+def test_format_captured_exceptions():
+    try:
+        raise ValueError('errors were made')
+    except ValueError:
+        exceptions = [sys.exc_info()]
+
+    obtained_text = format_captured_exceptions(exceptions)
+    lines = obtained_text.splitlines()
+
+    assert 'Qt exceptions in virtual methods:' in lines
+    assert 'ValueError: errors were made' in lines

pytestqt/plugin.py

@@ -213,26 +213,6 @@ def stopForInteraction(self):
     stop = stopForInteraction
 
 
-    @contextmanager
-    def _capture_exceptions(self):
-        """
-        Context manager that captures exceptions that happen insides it context,
-        and returns them as a list of (type, value, traceback) after the
-        context ends.
-        """
-        result = []
-
-        def hook(type_, value, tback):
-            result.append((type_, value, tback))
-            sys.__excepthook__(type_, value, tback)
-
-        sys.excepthook = hook
-        try:
-            yield result
-        finally:
-            sys.excepthook = sys.__excepthook__
-
-
 def pytest_configure(config):
     """
     PyTest plugin API. Called before the start of each test session, used
@@ -252,6 +232,40 @@ def exit_qapp():
     config._cleanup.append(exit_qapp)
 
 
+@contextmanager
+def capture_exceptions():
+    """
+    Context manager that captures exceptions that happen insides its context,
+    and returns them as a list of (type, value, traceback) after the
+    context ends.
+    """
+    result = []
+
+    def hook(type_, value, tback):
+        result.append((type_, value, tback))
+        sys.__excepthook__(type_, value, tback)
+
+    sys.excepthook = hook
+    try:
+        yield result
+    finally:
+        sys.excepthook = sys.__excepthook__
+
+
+def format_captured_exceptions(exceptions):
+    """
+    Formats exceptions given as (type, value, traceback) into a string
+    suitable to display as a test failure.
+    """
+    message = 'Qt exceptions in virtual methods:\n'
+    message += '_' * 80 + '\n'
+    for (exc_type, value, tback) in exceptions:
+        message += ''.join(traceback.format_tb(tback)) + '\n'
+        message += '%s: %s\n' % (exc_type.__name__, value)
+        message += '_' * 80 + '\n'
+    return message
+
+
 @pytest.yield_fixture
 def qtbot(request):
     """
@@ -261,17 +275,11 @@ def qtbot(request):
     that they are properly closed after the test ends.
     """
     result = QtBot(request.config.qt_app_instance)
-    with result._capture_exceptions() as exceptions:
+    with capture_exceptions() as exceptions:
         yield result
 
     if exceptions:
-        message = 'Qt exceptions in virtual methods:\n'
-        message += '_' * 80 + '\n'
-        for (exc_type, value, tback) in exceptions:
-            message += ''.join(traceback.format_tb(tback)) + '\n'
-            message += '%s: %s\n' % (exc_type.__name__, value)
-            message += '_' * 80 + '\n'
-        pytest.fail(message)
+        pytest.fail(format_captured_exceptions(exceptions))
 
     result._close()