Unit-test get_init_default_for_type

src/_pytest/config/argparsing.py

@@ -212,24 +212,27 @@ class Parser:
         """
         assert type in (None, "string", "paths", "pathlist", "args", "linelist", "bool")
         if default is NOT_SET:
-            default = self._get_ini_default_for_type(type)
+            default = get_ini_default_for_type(type)
 
         self._inidict[name] = (help, type, default)
         self._ininames.append(name)
 
-    def _get_ini_default_for_type(self, type) -> Any:
-        default = Any
+
+def get_ini_default_for_type(
+    type: Optional[Literal["string", "paths", "pathlist", "args", "linelist", "bool"]]
+) -> Any:
+    """
+    Used by addini to get the default value for a given ini-option type, when
+    default is not supplied.
+    """
     if type is None:
-            default = ""
-        else:
-            if type in ["paths", "pathlist", "args", "linelist"]:
-                default = []
+        return ""
+    elif type in ("paths", "pathlist", "args", "linelist"):
+        return []
     elif type == "bool":
-                default = False
+        return False
     else:
-                # for string type
-                default = ""
-        return default
+        return ""
 
 
 class ArgumentError(Exception):

testing/test_config.py

@@ -5,6 +5,7 @@ import re
 import sys
 import textwrap
 from pathlib import Path
+from typing import Any
 from typing import Dict
 from typing import List
 from typing import Sequence
@@ -21,6 +22,7 @@ from _pytest.config import Config
 from _pytest.config import ConftestImportFailure
 from _pytest.config import ExitCode
 from _pytest.config import parse_warning_filter
+from _pytest.config.argparsing import get_ini_default_for_type
 from _pytest.config.exceptions import UsageError
 from _pytest.config.findpaths import determine_setup
 from _pytest.config.findpaths import get_common_ancestor
@@ -904,6 +906,21 @@ class TestConfigAPI:
         value = config.getini("no_type")
         assert value == ""
 
+    @pytest.mark.parametrize(
+        "type, expected",
+        [
+            pytest.param(None, "", id="None"),
+            pytest.param("string", "", id="string"),
+            pytest.param("paths", [], id="paths"),
+            pytest.param("pathlist", [], id="pathlist"),
+            pytest.param("args", [], id="args"),
+            pytest.param("linelist", [], id="linelist"),
+            pytest.param("bool", False, id="bool"),
+        ],
+    )
+    def test_get_ini_default_for_type(self, type: Any, expected: Any) -> None:
+        assert get_ini_default_for_type(type) == expected
+
     def test_confcutdir_check_isdir(self, pytester: Pytester) -> None:
         """Give an error if --confcutdir is not a valid directory (#2078)"""
         exp_match = r"^--confcutdir must be a directory, given: "