CI: add a build against numpy nightly

.github/workflows/nightly-test.yml

@@ -0,0 +1,53 @@
+name: Test
+
+on:
+  # Trigger the workflow on push or pull request, but only on main branch
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+permissions:
+  contents: read  # to fetch code
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Python 3.9
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.9
+      - uses: pre-commit/[email protected]
+  build:
+    name: ${{ matrix.os }} Python ${{ matrix.python-version }} with nightly numpy
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: ["ubuntu-latest"]
+        python-version: ["3.12"]
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: true
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+            python -m pip install --upgrade pip
+            python -m pip install setuptools wheel
+            python -m pip install -U --pre numpy \
+              -i https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
+            python -c "import numpy; print(f'{numpy.__version__=}')"
+      - name: Build ml_dtypes
+        run: |
+            python -m pip install .[dev] --no-build-isolation
+      - name: Run tests
+        run: |
+          pytest -n auto

ml_dtypes/tests/custom_float_test.py

@@ -37,6 +37,14 @@
 float8_e5m2fnuz = ml_dtypes.float8_e5m2fnuz
 
 
+try:
+  # numpy >= 2.0
+  ComplexWarning = np.exceptions.ComplexWarning
+except AttributeError:
+  # numpy < 2.0
+  ComplexWarning = np.ComplexWarning
+
+
 @contextlib.contextmanager
 def ignore_warning(**kw):
   with warnings.catch_warnings():
@@ -703,7 +711,7 @@ def testCasts(self, float_type):
       self.assertTrue(np.all(x == z))
       self.assertEqual(dtype, z.dtype)
 
-  @ignore_warning(category=np.ComplexWarning)
+  @ignore_warning(category=ComplexWarning)
   def testConformNumpyComplex(self, float_type):
     for dtype in [np.complex64, np.complex128, np.clongdouble]:
       x = np.array([1.5, 2.5 + 2.0j, 3.5], dtype=dtype)

pytest.ini

@@ -1,3 +1,4 @@
 [pytest]
 filterwarnings =
     error
+    ignore:numpy.core._multiarray_umat.*:DeprecationWarning