gh-79871: IDLE - Fix and test debugger module (#11451)

Add docstrings to the debugger module. Fix two bugs: initialize Idb.botframe (should be in Bdb); In Idb.in_rpc_code, check whether prev_frame is None before trying to use it. Make other code changes.

Expand test_debugger coverage from 19% to 66%.
---------
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

1 files changed, 271 insertions, 5 deletions

diff --git a/Lib/idlelib/idle_test/test_debugger.py b/Lib/idlelib/idle_test/test_debugger.py
index 35efb34..db01a89 100644
--- a/Lib/idlelib/idle_test/test_debugger.py
+++ b/Lib/idlelib/idle_test/test_debugger.py
@@ -1,11 +1,279 @@
 "Test debugger, coverage 19%"
 
 from idlelib import debugger
-import unittest
-from test.support import requires
-requires('gui')
+from collections import namedtuple
+from textwrap import dedent
 from tkinter import Tk
 
+from test.support import requires
+import unittest
+from unittest import mock
+from unittest.mock import Mock, patch
+
+"""A test python script for the debug tests."""
+TEST_CODE = dedent("""
+    i = 1
+    i += 2
+    if i == 3:
+       print(i)
+    """)
+
+
+class MockFrame:
+    "Minimal mock frame."
+
+    def __init__(self, code, lineno):
+        self.f_code = code
+        self.f_lineno = lineno
+
+
+class IdbTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        cls.gui = Mock()
+        cls.idb = debugger.Idb(cls.gui)
+
+        # Create test and code objects to simulate a debug session.
+        code_obj = compile(TEST_CODE, 'idlelib/file.py', mode='exec')
+        frame1 = MockFrame(code_obj, 1)
+        frame1.f_back = None
+        frame2 = MockFrame(code_obj, 2)
+        frame2.f_back = frame1
+        cls.frame = frame2
+        cls.msg = 'file.py:2: <module>()'
+
+    def test_init(self):
+        # Test that Idb.__init_ calls Bdb.__init__.
+        idb = debugger.Idb(None)
+        self.assertIsNone(idb.gui)
+        self.assertTrue(hasattr(idb, 'breaks'))
+
+    def test_user_line(self):
+        # Test that .user_line() creates a string message for a frame.
+        self.gui.interaction = Mock()
+        self.idb.user_line(self.frame)
+        self.gui.interaction.assert_called_once_with(self.msg, self.frame)
+
+    def test_user_exception(self):
+        # Test that .user_exception() creates a string message for a frame.
+        exc_info = (type(ValueError), ValueError(), None)
+        self.gui.interaction = Mock()
+        self.idb.user_exception(self.frame, exc_info)
+        self.gui.interaction.assert_called_once_with(
+                self.msg, self.frame, exc_info)
+
+
+class FunctionTest(unittest.TestCase):
+    # Test module functions together.
+
+    def test_functions(self):
+        rpc_obj = compile(TEST_CODE,'rpc.py', mode='exec')
+        rpc_frame = MockFrame(rpc_obj, 2)
+        rpc_frame.f_back = rpc_frame
+        self.assertTrue(debugger._in_rpc_code(rpc_frame))
+        self.assertEqual(debugger._frame2message(rpc_frame),
+                         'rpc.py:2: <module>()')
+
+        code_obj = compile(TEST_CODE, 'idlelib/debugger.py', mode='exec')
+        code_frame = MockFrame(code_obj, 1)
+        code_frame.f_back = None
+        self.assertFalse(debugger._in_rpc_code(code_frame))
+        self.assertEqual(debugger._frame2message(code_frame),
+                         'debugger.py:1: <module>()')
+
+        code_frame.f_back = code_frame
+        self.assertFalse(debugger._in_rpc_code(code_frame))
+        code_frame.f_back = rpc_frame
+        self.assertTrue(debugger._in_rpc_code(code_frame))
+
+
+class DebuggerTest(unittest.TestCase):
+    "Tests for Debugger that do not need a real root."
+
+    @classmethod
+    def setUpClass(cls):
+        cls.pyshell = Mock()
+        cls.pyshell.root = Mock()
+        cls.idb = Mock()
+        with patch.object(debugger.Debugger, 'make_gui'):
+            cls.debugger = debugger.Debugger(cls.pyshell, cls.idb)
+        cls.debugger.root = Mock()
+
+    def test_cont(self):
+        self.debugger.cont()
+        self.idb.set_continue.assert_called_once()
+
+    def test_step(self):
+        self.debugger.step()
+        self.idb.set_step.assert_called_once()
+
+    def test_quit(self):
+        self.debugger.quit()
+        self.idb.set_quit.assert_called_once()
+
+    def test_next(self):
+        with patch.object(self.debugger, 'frame') as frame:
+            self.debugger.next()
+            self.idb.set_next.assert_called_once_with(frame)
+
+    def test_ret(self):
+        with patch.object(self.debugger, 'frame') as frame:
+            self.debugger.ret()
+            self.idb.set_return.assert_called_once_with(frame)
+
+    def test_clear_breakpoint(self):
+        self.debugger.clear_breakpoint('test.py', 4)
+        self.idb.clear_break.assert_called_once_with('test.py', 4)
+
+    def test_clear_file_breaks(self):
+        self.debugger.clear_file_breaks('test.py')
+        self.idb.clear_all_file_breaks.assert_called_once_with('test.py')
+
+    def test_set_load_breakpoints(self):
+        # Test the .load_breakpoints() method calls idb.
+        FileIO = namedtuple('FileIO', 'filename')
+
+        class MockEditWindow(object):
+            def __init__(self, fn, breakpoints):
+                self.io = FileIO(fn)
+                self.breakpoints = breakpoints
+
+        self.pyshell.flist = Mock()
+        self.pyshell.flist.inversedict = (
+            MockEditWindow('test1.py', [4, 4]),
+            MockEditWindow('test2.py', [13, 44, 45]),
+        )
+        self.debugger.set_breakpoint('test0.py', 1)
+        self.idb.set_break.assert_called_once_with('test0.py', 1)
+        self.debugger.load_breakpoints()  # Call set_breakpoint 5 times.
+        self.idb.set_break.assert_has_calls(
+            [mock.call('test0.py', 1),
+             mock.call('test1.py', 4),
+             mock.call('test1.py', 4),
+             mock.call('test2.py', 13),
+             mock.call('test2.py', 44),
+             mock.call('test2.py', 45)])
+
+    def test_sync_source_line(self):
+        # Test that .sync_source_line() will set the flist.gotofileline with fixed frame.
+        test_code = compile(TEST_CODE, 'test_sync.py', 'exec')
+        test_frame = MockFrame(test_code, 1)
+        self.debugger.frame = test_frame
+
+        self.debugger.flist = Mock()
+        with patch('idlelib.debugger.os.path.exists', return_value=True):
+            self.debugger.sync_source_line()
+        self.debugger.flist.gotofileline.assert_called_once_with('test_sync.py', 1)
+
+
+class DebuggerGuiTest(unittest.TestCase):
+    """Tests for debugger.Debugger that need tk root.
+
+    close needs debugger.top set in make_gui.
+    """
+
+    @classmethod
+    def setUpClass(cls):
+        requires('gui')
+        cls.root = root = Tk()
+        root.withdraw()
+        cls.pyshell = Mock()
+        cls.pyshell.root = root
+        cls.idb = Mock()
+# stack tests fail with debugger here.
+##        cls.debugger = debugger.Debugger(cls.pyshell, cls.idb)
+##        cls.debugger.root = root
+##        # real root needed for real make_gui
+##        # run, interacting, abort_loop
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.root.destroy()
+        del cls.root
+
+    def setUp(self):
+        self.debugger = debugger.Debugger(self.pyshell, self.idb)
+        self.debugger.root = self.root
+        # real root needed for real make_gui
+        # run, interacting, abort_loop
+
+    def test_run_debugger(self):
+        self.debugger.run(1, 'two')
+        self.idb.run.assert_called_once_with(1, 'two')
+        self.assertEqual(self.debugger.interacting, 0)
+
+    def test_close(self):
+        # Test closing the window in an idle state.
+        self.debugger.close()
+        self.pyshell.close_debugger.assert_called_once()
+
+    def test_show_stack(self):
+        self.debugger.show_stack()
+        self.assertEqual(self.debugger.stackviewer.gui, self.debugger)
+
+    def test_show_stack_with_frame(self):
+        test_frame = MockFrame(None, None)
+        self.debugger.frame = test_frame
+
+        # Reset the stackviewer to force it to be recreated.
+        self.debugger.stackviewer = None
+        self.idb.get_stack.return_value = ([], 0)
+        self.debugger.show_stack()
+
+        # Check that the newly created stackviewer has the test gui as a field.
+        self.assertEqual(self.debugger.stackviewer.gui, self.debugger)
+        self.idb.get_stack.assert_called_once_with(test_frame, None)
+
+
+class StackViewerTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        requires('gui')
+        cls.root = Tk()
+        cls.root.withdraw()
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.root.destroy()
+        del cls.root
+
+    def setUp(self):
+        self.code = compile(TEST_CODE, 'test_stackviewer.py', 'exec')
+        self.stack = [
+            (MockFrame(self.code, 1), 1),
+            (MockFrame(self.code, 2), 2)
+        ]
+        # Create a stackviewer and load the test stack.
+        self.sv = debugger.StackViewer(self.root, None, None)
+        self.sv.load_stack(self.stack)
+
+    def test_init(self):
+        # Test creation of StackViewer.
+        gui = None
+        flist = None
+        master_window = self.root
+        sv = debugger.StackViewer(master_window, flist, gui)
+        self.assertTrue(hasattr(sv, 'stack'))
+
+    def test_load_stack(self):
+        # Test the .load_stack() method against a fixed test stack.
+        # Check the test stack is assigned and the list contains the repr of them.
+        self.assertEqual(self.sv.stack, self.stack)
+        self.assertTrue('?.<module>(), line 1:' in self.sv.get(0))
+        self.assertEqual(self.sv.get(1), '?.<module>(), line 2: ')
+
+    def test_show_source(self):
+        # Test the .show_source() method against a fixed test stack.
+        # Patch out the file list to monitor it
+        self.sv.flist = Mock()
+        # Patch out isfile to pretend file exists.
+        with patch('idlelib.debugger.os.path.isfile', return_value=True) as isfile:
+            self.sv.show_source(1)
+            isfile.assert_called_once_with('test_stackviewer.py')
+            self.sv.flist.open.assert_called_once_with('test_stackviewer.py')
+
 
 class NameSpaceTest(unittest.TestCase):
 
@@ -23,7 +291,5 @@ class NameSpaceTest(unittest.TestCase):
         debugger.NamespaceViewer(self.root, 'Test')
 
 
-# Other classes are Idb, Debugger, and StackViewer.
-
 if __name__ == '__main__':
     unittest.main(verbosity=2)