Fix test_demos_run

tests/demos/test_demos_run.py

@@ -30,6 +30,10 @@
     "test_extrusion_lsw.py",
 ]
 
+parallel_demos = [
+    "full_waveform_inversion.py",
+]
+
 
 # Discover the demo files by globbing the demo directory
 @pytest.fixture(params=glob.glob("%s/*/*.py.rst" % demo_dir),
@@ -119,5 +123,9 @@ def test_demo_runs(py_file, env):
             import vtkmodules.vtkCommonDataModel  # noqa: F401
         except ImportError:
             pytest.skip(reason=f"VTK unavailable, skipping {basename(py_file)}")
+    if basename(py_file) in parallel_demos:
+        # Skip this test. It is expensive and reproduced in a simpler form
+        # at test/regression/test_fwi_demos.py
+        pytest.skip("Skipping parallel full waveform inversion (FWI) test")
 
     subprocess.check_call([sys.executable, py_file], env=env)