gh-119357: Increase test coverage for keymap in _pyrepl (#119358)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>

Lib/test/test_pyrepl/test_keymap.py

@@ -1,41 +1,78 @@
+import string
 import unittest
 
-from _pyrepl.keymap import parse_keys, compile_keymap
+from _pyrepl.keymap import _keynames, _escapes, parse_keys, compile_keymap, KeySpecError
 
 
 class TestParseKeys(unittest.TestCase):
     def test_single_character(self):
-        self.assertEqual(parse_keys("a"), ["a"])
-        self.assertEqual(parse_keys("b"), ["b"])
-        self.assertEqual(parse_keys("1"), ["1"])
+        """Ensure that single ascii characters or single digits are parsed as single characters."""
+        test_cases = [(key, [key]) for key in string.ascii_letters + string.digits]
+        for test_key, expected_keys in test_cases:
+            with self.subTest(f"{test_key} should be parsed as {expected_keys}"):
+                self.assertEqual(parse_keys(test_key), expected_keys)
+
+    def test_keynames(self):
+        """Ensure that keynames are parsed to their corresponding mapping.
+
+        A keyname is expected to be of the following form: \\<keyname> such as \\<left>
+        which would get parsed as "left".
+        """
+        test_cases = [(f"\\<{keyname}>", [parsed_keyname]) for keyname, parsed_keyname in _keynames.items()]
+        for test_key, expected_keys in test_cases:
+            with self.subTest(f"{test_key} should be parsed as {expected_keys}"):
+                self.assertEqual(parse_keys(test_key), expected_keys)
 
     def test_escape_sequences(self):
-        self.assertEqual(parse_keys("\\n"), ["\n"])
-        self.assertEqual(parse_keys("\\t"), ["\t"])
-        self.assertEqual(parse_keys("\\\\"), ["\\"])
-        self.assertEqual(parse_keys("\\'"), ["'"])
-        self.assertEqual(parse_keys('\\"'), ['"'])
+        """Ensure that escaping sequences are parsed to their corresponding mapping."""
+        test_cases = [(f"\\{escape}", [parsed_escape]) for escape, parsed_escape in _escapes.items()]
+        for test_key, expected_keys in test_cases:
+            with self.subTest(f"{test_key} should be parsed as {expected_keys}"):
+                self.assertEqual(parse_keys(test_key), expected_keys)
 
     def test_control_sequences(self):
-        self.assertEqual(parse_keys("\\C-a"), ["\x01"])
-        self.assertEqual(parse_keys("\\C-b"), ["\x02"])
-        self.assertEqual(parse_keys("\\C-c"), ["\x03"])
+        """Ensure that supported control sequences are parsed successfully."""
+        keys = ["@", "[", "]", "\\", "^", "_", "\\<space>", "\\<delete>"]
+        keys.extend(string.ascii_letters)
+        test_cases = [(f"\\C-{key}", chr(ord(key) & 0x1F)) for key in []]
+        for test_key, expected_keys in test_cases:
+            with self.subTest(f"{test_key} should be parsed as {expected_keys}"):
+                self.assertEqual(parse_keys(test_key), expected_keys)
 
     def test_meta_sequences(self):
         self.assertEqual(parse_keys("\\M-a"), ["\033", "a"])
         self.assertEqual(parse_keys("\\M-b"), ["\033", "b"])
         self.assertEqual(parse_keys("\\M-c"), ["\033", "c"])
 
-    def test_keynames(self):
-        self.assertEqual(parse_keys("\\<up>"), ["up"])
-        self.assertEqual(parse_keys("\\<down>"), ["down"])
-        self.assertEqual(parse_keys("\\<left>"), ["left"])
-        self.assertEqual(parse_keys("\\<right>"), ["right"])
-
     def test_combinations(self):
         self.assertEqual(parse_keys("\\C-a\\n\\<up>"), ["\x01", "\n", "up"])
         self.assertEqual(parse_keys("\\M-a\\t\\<down>"), ["\033", "a", "\t", "down"])
 
+    def test_keyspec_errors(self):
+        cases = [
+            ("\\Ca", "\\C must be followed by `-'"),
+            ("\\ca", "\\C must be followed by `-'"),
+            ("\\C-\\C-", "doubled \\C-"),
+            ("\\Ma", "\\M must be followed by `-'"),
+            ("\\ma", "\\M must be followed by `-'"),
+            ("\\M-\\M-", "doubled \\M-"),
+            ("\\<left", "unterminated \\<"),
+            ("\\<unsupported>", "unrecognised keyname"),
+            ("\\大", "unknown backslash escape"),
+            ("\\C-\\<backspace>", "\\C- followed by invalid key")
+        ]
+        for test_keys, expected_err in cases:
+            with self.subTest(f"{test_keys} should give error {expected_err}"):
+                with self.assertRaises(KeySpecError) as e:
+                    parse_keys(test_keys)
+                self.assertIn(expected_err, str(e.exception))
+
+    def test_index_errors(self):
+        test_cases = ["\\", "\\C", "\\C-\\C"]
+        for test_keys in test_cases:
+            with self.assertRaises(IndexError):
+                parse_keys(test_keys)
+
 
 class TestCompileKeymap(unittest.TestCase):
     def test_empty_keymap(self):
@@ -72,3 +109,12 @@ class TestCompileKeymap(unittest.TestCase):
         keymap = {b"a": {b"b": {b"c": "action"}}}
         result = compile_keymap(keymap)
         self.assertEqual(result, {b"a": {b"b": {b"c": "action"}}})
+
+    def test_clashing_definitions(self):
+        km = {b'a': 'c', b'a' + b'b': 'd'}
+        with self.assertRaises(KeySpecError):
+            compile_keymap(km)
+
+    def test_non_bytes_key(self):
+        with self.assertRaises(TypeError):
+            compile_keymap({123: 'a'})