From b9fee08c5911dcdb38d320260589cce3229c5c72 Mon Sep 17 00:00:00 2001
From: DWesl <22566757+DWesl@users.noreply.github.com>
Date: Sat, 18 Dec 2021 10:00:14 -0500
Subject: [PATCH] TST: Parametrize numpy roundtrip to find failing case

Segfaults are annoying to debug.
---
 .github/workflows/test-cygwin.yml |  2 ++
 Tests/test_numpy.py               | 13 ++++++++-----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/test-cygwin.yml b/.github/workflows/test-cygwin.yml
index d3ab0a361..b6a305b71 100644
--- a/.github/workflows/test-cygwin.yml
+++ b/.github/workflows/test-cygwin.yml
@@ -38,6 +38,7 @@ jobs:
         run: |
           C:\tools\cygwin\bin\python3.8 -m pip install pip wheel setuptools
           C:\tools\cygwin\bin\python3.8 -m pip install -r requirements.txt
+          C:\tools\cygwin\bin\python3.8 -m pip install pytest-forked
 
       - name: Build Pillow
         run: |
@@ -56,6 +57,7 @@ jobs:
           C:\tools\cygwin\bin\mv .ci/test.sh .ci/test.sh.dos
           C:\tools\cygwin\bin\dash -c "/bin/tr -d '\r' <.ci/test.sh.dos >.ci/test.sh"
           C:\tools\cygwin\bin\chmod u+x .ci/test.sh
+          C:\tools\cygwin\bin\python3.8 -m pytest --forked Tests/test_numpy.py -k roundtrip
           C:\tools\cygwin\bin\dash /usr/bin/xvfb-run -s '-screen 0 1024x768x24' .ci/test.sh .8
 
       - name: After success
diff --git a/Tests/test_numpy.py b/Tests/test_numpy.py
index def7adf3f..936474fe8 100644
--- a/Tests/test_numpy.py
+++ b/Tests/test_numpy.py
@@ -189,8 +189,9 @@ def test_putdata():
     assert len(im.getdata()) == len(arr)
 
 
-def test_roundtrip_eye():
-    for dtype in (
+@pytest.mark.parametrize(
+    "dtype",
+    (
         bool,
         numpy.bool8,
         numpy.int8,
@@ -202,9 +203,11 @@ def test_roundtrip_eye():
         float,
         numpy.float32,
         numpy.float64,
-    ):
-        arr = numpy.eye(10, dtype=dtype)
-        numpy.testing.assert_array_equal(arr, numpy.array(Image.fromarray(arr)))
+    ),
+)
+def test_roundtrip_eye(dtype):
+    arr = numpy.eye(10, dtype=dtype)
+    numpy.testing.assert_array_equal(arr, numpy.array(Image.fromarray(arr)))
 
 
 def test_zero_size():