chore: use pytest's new strict mode and fix duplicate tests

pyproject.toml

@@ -43,7 +43,7 @@ pre-commit = ">=2.15.0"
 vendoring = ">=1.0"
 
 [tool.poetry.group.test.dependencies]
-pytest = ">=7.1.2"
+pytest = ">=9.0"
 pytest-cov = ">=3.0.0"
 pytest-mock = ">=3.10"
 build = ">=0.10.0"
@@ -132,6 +132,9 @@ module = [
 ]
 ignore_missing_imports = true
 
+[tool.pytest]
+strict = true
+
 [tool.vendoring]
 destination = "src/poetry/core/_vendor/"
 requirements = "src/poetry/core/_vendor/vendor.txt"

tests/constraints/version/test_version_range.py

@@ -86,7 +86,6 @@ def v300b1() -> Version:
         ("<=3.0.0", "3.0.0+local.1", True),
         (">=3.0.0", "3.0.0", True),
         (">=3.0.0", "3.0.0+local.1", True),
-        (">=3.0.0", "3.0.0", True),
         (">=3.0.0", "3.0.0-1", True),
         ("<=3.0.0+local.1", "3.0.0", True),
         ("<=3.0.0+local.1", "3.0.0+local.1", True),

tests/masonry/builders/test_builder.py

@@ -1,7 +1,5 @@
 from __future__ import annotations
 
-import sys
-
 from email.parser import Parser
 from pathlib import Path
 from typing import TYPE_CHECKING
@@ -63,10 +61,6 @@ def test_builder_find_excluded_files_dirs(mocker: MockerFixture) -> None:
     }
 
 
-@pytest.mark.xfail(
-    sys.platform == "win32",
-    reason="Windows is case insensitive for the most part",
-)
 def test_builder_find_case_sensitive_excluded_files(mocker: MockerFixture) -> None:
     mocker.patch("poetry.core.vcs.git.Git.get_ignored_files", return_value=[])
 
@@ -87,10 +81,6 @@ def test_builder_find_case_sensitive_excluded_files(mocker: MockerFixture) -> No
     }
 
 
-@pytest.mark.xfail(
-    sys.platform == "win32",
-    reason="Windows is case insensitive for the most part",
-)
 def test_builder_find_invalid_case_sensitive_excluded_files(
     mocker: MockerFixture,
 ) -> None:

tests/version/test_markers.py

@@ -187,7 +187,7 @@ def test_single_marker_intersect() -> None:
         ('python_version >= "3.6"', 'python_version < "3.6"'),
         ('python_version == "3.6"', 'python_version == "3.7"'),
         ('python_version > "3.6"', 'python_version <= "3.6"'),
-        ('python_version >= "3.6"', 'python_version < "3.6"'),
+        ('python_version > "3.6"', 'python_version < "3.6"'),
         ('python_version > "3.6"', 'python_version < "3.7"'),
     ],
 )
@@ -931,14 +931,6 @@ def test_multi_marker_union_multi_is_multi(
             ),
             'python_version >= "3.8" and python_version < "3.10"',
         ),
-        (
-            'python_version == "3.8" or python_version == "3.9"',
-            (
-                'python_version >= "3.8" and python_version <= "3.9"'
-                ' and sys_platform == "linux"'
-            ),
-            'python_version >= "3.8" and python_version < "3.10"',
-        ),
         (
             'python_version == "3.8" or python_version == "3.9"',
             (