From 8d396cb5067dc404fb1624a6de8f747f23bda114 Mon Sep 17 00:00:00 2001
From: Bas van Beek <43369155+BvB93@users.noreply.github.com>
Date: Fri, 10 Apr 2020 17:01:48 +0200
Subject: [PATCH 1/5] Fixed an issue where .pyi files were ignored

---
 src/pytest_mypy.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/pytest_mypy.py b/src/pytest_mypy.py
index 9714cab..551aea9 100644
--- a/src/pytest_mypy.py
+++ b/src/pytest_mypy.py
@@ -75,7 +75,7 @@ def pytest_configure_node(self, node):  # xdist hook
 
 def pytest_collect_file(path, parent):
     """Create a MypyFileItem for every file mypy should run on."""
-    if path.ext == '.py' and any([
+    if path.ext in {'.py', '.pyi'} and any([
             parent.config.option.mypy,
             parent.config.option.mypy_ignore_missing_imports,
     ]):

From f6aca0a355997d4e913f26bf4de14066c215723e Mon Sep 17 00:00:00 2001
From: Bas van Beek <43369155+BvB93@users.noreply.github.com>
Date: Fri, 10 Apr 2020 18:14:08 +0200
Subject: [PATCH 2/5] Skip a .py file if an identically named .pyi file already
 exists

Skip a .py file if an identically named .pyi file already exists as pytest will complain about duplicate modules otherwise.
---
 src/pytest_mypy.py | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/pytest_mypy.py b/src/pytest_mypy.py
index 551aea9..fc4d9b2 100644
--- a/src/pytest_mypy.py
+++ b/src/pytest_mypy.py
@@ -79,7 +79,17 @@ def pytest_collect_file(path, parent):
             parent.config.option.mypy,
             parent.config.option.mypy_ignore_missing_imports,
     ]):
-        return MypyFile.from_parent(parent=parent, fspath=path)
+        if path.ext == '.pyi':
+            return MypyFile.from_parent(parent=parent, fspath=path)
+
+        # Do not create MypyFile instance for a .py file if a
+        # .pyi file with the same name already exists;
+        # pytest will complain about duplicate modules otherwise
+        path_pyi = str(path) + 'i'  # i.e. a .pyi instead of a .py file
+        if os.path.isfile(path_pyi):
+            return None
+        else:
+            return MypyFile.from_parent(parent=parent, fspath=path)
     return None
 
 

From f59e36c3b9a9db25323b7eb3862fde42bc815607 Mon Sep 17 00:00:00 2001
From: Bas van Beek <43369155+BvB93@users.noreply.github.com>
Date: Fri, 10 Apr 2020 18:16:56 +0200
Subject: [PATCH 3/5] Removed a redundant if/else statement

---
 src/pytest_mypy.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/pytest_mypy.py b/src/pytest_mypy.py
index fc4d9b2..c6e4b9b 100644
--- a/src/pytest_mypy.py
+++ b/src/pytest_mypy.py
@@ -86,9 +86,7 @@ def pytest_collect_file(path, parent):
         # .pyi file with the same name already exists;
         # pytest will complain about duplicate modules otherwise
         path_pyi = str(path) + 'i'  # i.e. a .pyi instead of a .py file
-        if os.path.isfile(path_pyi):
-            return None
-        else:
+        if not os.path.isfile(path_pyi):
             return MypyFile.from_parent(parent=parent, fspath=path)
     return None
 

From b2e175099b96d0a9b0135db7673b569c5f928903 Mon Sep 17 00:00:00 2001
From: Bas van Beek <b.f.van.beek@vu.nl>
Date: Fri, 10 Apr 2020 21:28:39 +0200
Subject: [PATCH 4/5] Added a test for .pyi files

---
 tests/test_pytest_mypy.py | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/tests/test_pytest_mypy.py b/tests/test_pytest_mypy.py
index 789405d..d00e824 100644
--- a/tests/test_pytest_mypy.py
+++ b/tests/test_pytest_mypy.py
@@ -36,6 +36,36 @@ def pyfunc(x: int) -> int:
     assert result.ret == 0
 
 
+def test_mypy_pyi(testdir, xdist_args):
+    """
+    Verify that a .py file will be skipped if
+    a .pyi file exists with the same filename.
+    """
+    # The incorrect signature below should be ignored
+    # as the .pyi file takes priority
+    testdir.makefile(
+        '.py', pyfile='''
+            def pyfunc(x: int) -> str:
+                return x * 2
+        '''
+    )
+
+    testdir.makefile(
+        '.pyi', pyfile='''
+            def pyfunc(x: int) -> int: ...
+        '''
+    )
+
+    result = testdir.runpytest_subprocess(*xdist_args)
+    result.assert_outcomes()
+    result = testdir.runpytest_subprocess('--mypy', *xdist_args)
+    mypy_file_checks = 1
+    mypy_status_check = 1
+    mypy_checks = mypy_file_checks + mypy_status_check
+    result.assert_outcomes(passed=mypy_checks)
+    assert result.ret == 0
+
+
 def test_mypy_error(testdir, xdist_args):
     """Verify that running on a module with type errors fails."""
     testdir.makepyfile('''

From 063ce40b8bfd35d729c7a120bdba51d9ad7bcce0 Mon Sep 17 00:00:00 2001
From: Bas van Beek <b.f.van.beek@vu.nl>
Date: Sun, 12 Apr 2020 14:38:47 +0200
Subject: [PATCH 5/5] Implemented
 https://github.com/dbader/pytest-mypy/pull/84#discussion_r407021212

---
 src/pytest_mypy.py | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/pytest_mypy.py b/src/pytest_mypy.py
index c6e4b9b..7c2ca8d 100644
--- a/src/pytest_mypy.py
+++ b/src/pytest_mypy.py
@@ -79,14 +79,10 @@ def pytest_collect_file(path, parent):
             parent.config.option.mypy,
             parent.config.option.mypy_ignore_missing_imports,
     ]):
-        if path.ext == '.pyi':
-            return MypyFile.from_parent(parent=parent, fspath=path)
-
         # Do not create MypyFile instance for a .py file if a
         # .pyi file with the same name already exists;
         # pytest will complain about duplicate modules otherwise
-        path_pyi = str(path) + 'i'  # i.e. a .pyi instead of a .py file
-        if not os.path.isfile(path_pyi):
+        if path.ext == '.pyi' or not path.new(ext='.pyi').isfile():
             return MypyFile.from_parent(parent=parent, fspath=path)
     return None