diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0426ed7..1726013 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,16 +21,19 @@ jobs:
           linux: test
           os: ubuntu-latest
           python-version: 3.11
+          toxposargs: --remote-data
 
         - name: py3.12
           linux: test
           os: ubuntu-latest
           python-version: 3.12
+          toxposargs: --remote-data
 
         - name: py3.13
           linux: test
           os: ubuntu-latest
           python-version: 3.13
+          toxposargs: --remote-data
 
         - name: Code style checks
           python: 3.11
@@ -42,7 +45,6 @@ jobs:
           os: ubuntu-latest
           python: '3.12'
           toxenv: py312-test-cov
-          toxposargs: --remote-data
 
   cov:
     name: Coverage
@@ -61,7 +63,7 @@ jobs:
           pip install pytest pytest-cov pytest-doctestplus pytest-remotedata .
 
       - name: Run tests
-        run: pytest --cov --cov-branch --cov-report=xml
+        run: pytest --cov --cov-branch --cov-report=xml --remote-data
 
       - name: Upload results to Codecov
         uses: codecov/codecov-action@v5
diff --git a/opacity/tests/__init__.py b/opacity/tests/__init__.py
index 92ea707..e69de29 100644
--- a/opacity/tests/__init__.py
+++ b/opacity/tests/__init__.py
@@ -1,3 +0,0 @@
-"""
-This module contains package tests.
-"""
diff --git a/opacity/tests/test_dataset.py b/opacity/tests/test_dataset.py
index 1f0dfe1..9994ef1 100644
--- a/opacity/tests/test_dataset.py
+++ b/opacity/tests/test_dataset.py
@@ -28,16 +28,23 @@
 
 @pytest.mark.remote_data
 @pytest.mark.parametrize(
-    "species, coord, expected", [
-        ('H2O', 'temperature', grid1460_temperature),
-        ('H2O', 'pressure', grid1460_pressure),
-        ('VO', 'temperature', grid1460_temperature),
-        ('VO', 'pressure', grid1460_pressure),
+    "species, coord, expected, set_local_cache_store,", [
+        ('H2O', 'temperature', grid1460_temperature, True),
+        ('H2O', 'pressure', grid1460_pressure, False),
+        ('VO', 'temperature', grid1460_temperature, True),
+        ('VO', 'pressure', grid1460_pressure, False),
     ]
 )
-def test_open_dataset_cache_coordinates(tmpdir, species, coord, expected):
+def test_open_dataset_cache_coordinates(
+    tmpdir, species, coord, expected, set_local_cache_store
+):
     tmp_path = os.path.join(tmpdir, species + '.zarr')
-    local_cache_store = zarr.storage.LocalStore(tmp_path)
+
+    if set_local_cache_store:
+        local_cache_store = zarr.storage.LocalStore(tmp_path)
+    else:
+        local_cache_store = None
+
     ds = open_dataset(
         species=species,
         cache_path=tmp_path,
@@ -63,3 +70,15 @@ def test_open_dataset_nocache_coordinates(tmpdir, species, coord, expected):
         max_cache_size_gb=1e-3
     )
     assert all(ds[coord] == expected)
+
+
+def test_open_dataset_no_species(tmpdir, species=None):
+    with pytest.raises(
+        ValueError,
+        match="opacity.open_dataset requires a species*"
+    ):
+        _ = open_dataset(
+            species=species,
+            cache=False,
+            max_cache_size_gb=1e-3
+        )
diff --git a/opacity/tests/test_filesystem.py b/opacity/tests/test_filesystem.py
index 6c09be9..be88e2c 100644
--- a/opacity/tests/test_filesystem.py
+++ b/opacity/tests/test_filesystem.py
@@ -2,6 +2,7 @@
 from opacity import get_available_datasets
 
 
+@pytest.mark.remote_data
 @pytest.mark.parametrize(
     "zarr_name,",
     [