Emit a correct invalid-name message when using multi-naming style. (#4924)

* Emit a correct invalid-name message when using multi-naming style.

Previously, given `--function-rgx=(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$` and the code:

```
def FOO():
    pass
def UPPER():
    pass
def lower():
    pass
```

It would emit a message: ``Function name `lower` doesn't conform to '(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern [invalid-name]``.

The message is misleading as `lower` *does* conform to `(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$`. It's just not the prevalent group "UP".

After this commit, the message becomes: ``Function name `lower` doesn't conform to UP group in the '(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern [invalid-name]``

Co-authored-by: Pierre Sassoulas <pierre.sassoulas@gmail.com>

4 files changed, 28 insertions, 4 deletions

diff --git a/tests/checkers/unittest_base.py b/tests/checkers/unittest_base.py
index 7121f257f..6a20db922 100644
--- a/tests/checkers/unittest_base.py
+++ b/tests/checkers/unittest_base.py
@@ -303,7 +303,11 @@ class TestMultiNamingStyle(CheckerTestCase):
         message = Message(
             "invalid-name",
             node=classes[0],
-            args=("Class", "classb", "'(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern"),
+            args=(
+                "Class",
+                "classb",
+                "the `UP` group in the '(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern",
+            ),
         )
         with self.assertAddsMessages(message):
             cls = None
@@ -340,7 +344,7 @@ class TestMultiNamingStyle(CheckerTestCase):
                 args=(
                     "Class",
                     "CLASSC",
-                    "'(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern",
+                    "the `down` group in the '(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern",
                 ),
             ),
         ]
@@ -371,7 +375,11 @@ class TestMultiNamingStyle(CheckerTestCase):
         message = Message(
             "invalid-name",
             node=function_defs[1],
-            args=("Function", "FUNC", "'(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern"),
+            args=(
+                "Function",
+                "FUNC",
+                "the `down` group in the '(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern",
+            ),
         )
         with self.assertAddsMessages(message):
             func = None
@@ -402,7 +410,7 @@ class TestMultiNamingStyle(CheckerTestCase):
             args=(
                 "Function",
                 "UPPER",
-                "'(?:(?P<ignore>FOO)|(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern",
+                "the `down` group in the '(?:(?P<ignore>FOO)|(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern",
             ),
         )
         with self.assertAddsMessages(message):
diff --git a/tests/functional/i/invalid/invalid_name_multinaming_style.py b/tests/functional/i/invalid/invalid_name_multinaming_style.py
new file mode 100644
index 000000000..561a15472
--- /dev/null
+++ b/tests/functional/i/invalid/invalid_name_multinaming_style.py
@@ -0,0 +1,13 @@
+"""Test for multi naming style."""
+
+
+def UPPER():  # [invalid-name]
+    """UPPER func that will generate invalid-name error."""
+
+
+def lower():
+    """lower func that satisfies the prevalent group `lower`."""
+
+
+def anotherlower():
+    """Another lower func that satisfies the prevalent group `lower`."""
diff --git a/tests/functional/i/invalid/invalid_name_multinaming_style.rc b/tests/functional/i/invalid/invalid_name_multinaming_style.rc
new file mode 100644
index 000000000..d513cfbff
--- /dev/null
+++ b/tests/functional/i/invalid/invalid_name_multinaming_style.rc
@@ -0,0 +1,2 @@
+[BASIC]
+function-rgx=^(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$
diff --git a/tests/functional/i/invalid/invalid_name_multinaming_style.txt b/tests/functional/i/invalid/invalid_name_multinaming_style.txt
new file mode 100644
index 000000000..abcde057e
--- /dev/null
+++ b/tests/functional/i/invalid/invalid_name_multinaming_style.txt
@@ -0,0 +1 @@
+invalid-name:4:0:UPPER:"Function name ""UPPER"" doesn't conform to the `down` group in the '^(?:(?P<UP>[A-Z]+)|(?P<down>[a-z]+))$' pattern":HIGH