diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 5a53d4d..b9ba7de 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -33,13 +33,18 @@ jobs:
       run: |
         micromamba create --name TEST python=${{ matrix.python-version }} python-build numpy=${{ matrix.numpy-version }} --file requirements-dev.txt --channel conda-forge
         micromamba activate TEST
-        pip install -e . --no-deps --force-reinstall
+        python -m pip install -e . --no-deps --no-build-isolation --force-reinstall
+
+    - name: Debug
+      shell: bash -l {0}
+      run: |
+        micromamba activate TEST
         micromamba info --all
         micromamba list
+        python -c "import numpy; print(f'Running numpy {numpy.__version__}')"
 
     - name: Tests
       shell: bash -l {0}
       run: |
         micromamba activate TEST
-        python -c "import numpy; print(f'Running numpy {numpy.__version__}')"
         pytest -s -rxs -v gsw/tests
diff --git a/gsw/geostrophy.py b/gsw/geostrophy.py
index 7c7104e..42e2328 100644
--- a/gsw/geostrophy.py
+++ b/gsw/geostrophy.py
@@ -184,8 +184,9 @@ def distance(lon, lat, p=0, axis=-1):
                           % (lon.shape, axis))
     if lon.ndim == 1:
         one_d = True
-        lon = lon[np.newaxis, :]
-        lat = lat[np.newaxis, :]
+        # xarray requires expand_dims() rather than [newaxis, :]
+        lon = np.expand_dims(lon, 0)
+        lat = np.expand_dims(lat, 0)
         axis = -1
     else:
         one_d = False
diff --git a/pyproject.toml b/pyproject.toml
index 820e39e..5bc1231 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,3 +1,3 @@
 [build-system]
-requires = ["pip >9.0.1", "setuptools>=42", "wheel", "setuptools_scm[toml]>=3.4", "oldest-supported-numpy", "build"]
+requires = ["pip>9.0.1", "setuptools>=42", "wheel", "setuptools_scm[toml]>=3.4", "oldest-supported-numpy", "build"]
 build-backend = "setuptools.build_meta"