Skip typing.NoReturn tests on Python < 3.6.2

typing.NoReturn was introduced in Python 3.6.2. Move the tests for
issue pylint-dev#4122 to a separate file and skip when Python is too old.

tests/functional/i/inconsistent/inconsistent_returns.py

@@ -336,59 +336,6 @@ def bug_pylint_3873_2():
         nothing_to_do()
     return False
 
-import typing  # pylint: disable=wrong-import-position
-
-def parser_error(msg) -> typing.NoReturn:  #pylint:disable=unused-argument
-    sys.exit(1)
-
-def parser_error_nortype(msg):  #pylint:disable=unused-argument
-    sys.exit(2)
-
-
-from typing import NoReturn  # pylint: disable=wrong-import-position
-
-def parser_error_name(msg) -> NoReturn:  #pylint:disable=unused-argument
-    sys.exit(3)
-
-def bug_pylint_4122(s):
-    """
-    Every returns is consistent because parser_error has type hints
-    indicating it never returns
-    """
-    try:
-        n = int(s)
-        if n < 1:
-            raise ValueError()
-        return n
-    except ValueError:
-        parser_error('parser error')
-
-def bug_pylint_4122_wrong(s): # [inconsistent-return-statements]
-    """
-    Every returns is not consistent because parser_error_nortype has no type hints
-    """
-    try:
-        n = int(s)
-        if n < 1:
-            raise ValueError()
-        return n
-    except ValueError:
-        parser_error_nortype('parser error')
-
-def bug_pylint_4122_bis(s):
-    """
-    Every returns is consistent because parser_error has type hints
-    indicating it never returns
-    """
-    try:
-        n = int(s)
-        if n < 1:
-            raise ValueError()
-        return n
-    except ValueError:
-        parser_error_name('parser error')
-
-
 # https://github.com/PyCQA/pylint/issues/4019
 def bug_pylint_4019(x):
     """

tests/functional/i/inconsistent/inconsistent_returns.txt

@@ -14,5 +14,4 @@ inconsistent-return-statements:262:8:bug_1794_inner_func_in_if_counter_example_3
 inconsistent-return-statements:267:0:bug_3468:Either all return statements in a function should return an expression, or none of them should.
 inconsistent-return-statements:277:0:bug_3468_variant:Either all return statements in a function should return an expression, or none of them should.
 inconsistent-return-statements:322:0:bug_pylint_3873_1:Either all return statements in a function should return an expression, or none of them should.
-inconsistent-return-statements:366:0:bug_pylint_4122_wrong:Either all return statements in a function should return an expression, or none of them should.
-inconsistent-return-statements:402:0:bug_pylint_4019_wrong:Either all return statements in a function should return an expression, or none of them should.
+inconsistent-return-statements:349:0:bug_pylint_4019_wrong:Either all return statements in a function should return an expression, or none of them should.

tests/functional/i/inconsistent/inconsistent_returns_noreturn.py

@@ -0,0 +1,55 @@
+#pylint: disable=missing-docstring, invalid-name
+"""Testing inconsistent returns involving typing.NoReturn annotations."""
+
+import sys
+import typing
+
+def parser_error(msg) -> typing.NoReturn:  #pylint:disable=unused-argument
+    sys.exit(1)
+
+def parser_error_nortype(msg):  #pylint:disable=unused-argument
+    sys.exit(2)
+
+
+from typing import NoReturn  # pylint: disable=wrong-import-position
+
+def parser_error_name(msg) -> NoReturn:  #pylint:disable=unused-argument
+    sys.exit(3)
+
+def bug_pylint_4122(s):
+    """
+    Every returns is consistent because parser_error has type hints
+    indicating it never returns
+    """
+    try:
+        n = int(s)
+        if n < 1:
+            raise ValueError()
+        return n
+    except ValueError:
+        parser_error('parser error')
+
+def bug_pylint_4122_wrong(s): # [inconsistent-return-statements]
+    """
+    Every returns is not consistent because parser_error_nortype has no type hints
+    """
+    try:
+        n = int(s)
+        if n < 1:
+            raise ValueError()
+        return n
+    except ValueError:
+        parser_error_nortype('parser error')
+
+def bug_pylint_4122_bis(s):
+    """
+    Every returns is consistent because parser_error has type hints
+    indicating it never returns
+    """
+    try:
+        n = int(s)
+        if n < 1:
+            raise ValueError()
+        return n
+    except ValueError:
+        parser_error_name('parser error')

tests/functional/i/inconsistent/inconsistent_returns_noreturn.rc

@@ -0,0 +1,5 @@
+[testoptions]
+min_pyver=3.6.2
+
+[REFACTORING]
+never-returning-functions=sys.exit,sys.getdefaultencoding

tests/functional/i/inconsistent/inconsistent_returns_noreturn.txt

@@ -0,0 +1 @@
+inconsistent-return-statements:32:0:bug_pylint_4122_wrong:Either all return statements in a function should return an expression, or none of them should.