diff --git a/pvnet_app/app.py b/pvnet_app/app.py
index 5bc6b53..6250eb6 100644
--- a/pvnet_app/app.py
+++ b/pvnet_app/app.py
@@ -218,7 +218,8 @@ def app(
             # Store the config filename so we can create batches suitable for all models
             data_config_paths.append(data_config_path)
         else:
-            warnings.warn(f"The model {model_config.name} cannot be run with input data available")
+            message = f"The model {model_config.name} cannot be run with input data available"
+            warnings.warn(message)
 
     if len(forecast_compilers) == 0:
         raise Exception(f"No models were compatible with the available input data.")
diff --git a/tests/conftest.py b/tests/conftest.py
index 0194e15..8bca352 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -20,7 +20,7 @@
 
 xr.set_options(keep_attrs=True)
 
-@pytest.fixture()
+@pytest.fixture(scope="module")
 def test_t0():
     return pd.Timestamp.now(tz=None).floor(timedelta(minutes=30))
 
@@ -115,7 +115,7 @@ def make_nwp_data(shell_path, varname, test_t0):
     return ds
         
 
-@pytest.fixture
+@pytest.fixture(scope="module")
 def nwp_ukv_data(test_t0):
     return make_nwp_data(
         shell_path=f"{os.path.dirname(os.path.abspath(__file__))}/test_data/nwp_ukv_shell.zarr",
@@ -124,7 +124,7 @@ def nwp_ukv_data(test_t0):
     )
 
 
-@pytest.fixture
+@pytest.fixture(scope="module")
 def nwp_ecmwf_data(test_t0):
     return make_nwp_data(
         shell_path=f"{os.path.dirname(os.path.abspath(__file__))}/test_data/nwp_ecmwf_shell.zarr",
@@ -168,20 +168,20 @@ def make_sat_data(test_t0, delay_mins, freq_mins):
 
     return ds
 
-@pytest.fixture()
+@pytest.fixture(scope="module")
 def sat_5_data(test_t0):
     return make_sat_data(test_t0, delay_mins=10, freq_mins=5)
 
-@pytest.fixture()
+@pytest.fixture(scope="module")
 def sat_5_data_zero_delay(test_t0):
     return make_sat_data(test_t0, delay_mins=0, freq_mins=5)
 
-@pytest.fixture()
+@pytest.fixture(scope="module")
 def sat_5_data_delayed(test_t0):
     return make_sat_data(test_t0, delay_mins=120, freq_mins=5)
 
 
-@pytest.fixture()
+@pytest.fixture(scope="module")
 def sat_15_data(test_t0):
     return make_sat_data(test_t0, delay_mins=0, freq_mins=15)