diff --git a/conftest.py b/conftest.py
index 743b3562e9e4185a373b97eaaa0fb70813c16c13..d21cab65e83e844d7ea6ebb1c01e3ac6baddf8d3 100644
--- a/conftest.py
+++ b/conftest.py
@@ -46,6 +46,11 @@ except ImportError:
     collect_ignore += [os.path.join(SCRIPT_FOLDER, "lbmpy_tests/test_serial_scenarios.py")]
     collect_ignore += [os.path.join(SCRIPT_FOLDER, "lbmpy_tests/test_datahandling_parallel.py")]
 
+try:
+    import blitzdb
+except ImportError:
+    collect_ignore += [os.path.join(SCRIPT_FOLDER, "lbmpy_tests/benchmark"),
+                       os.path.join(SCRIPT_FOLDER, "lbmpy_tests/full_scenarios/kida_vortex_flow/scenario_kida_vortex_flow.py")]
 
 collect_ignore += [os.path.join(SCRIPT_FOLDER, 'setup.py')]
 
@@ -104,7 +109,7 @@ class IPyNbFile(pytest.File):
         exporter.exclude_markdown = True
         exporter.exclude_input_prompt = True
 
-        notebook_contents = self.fspath.open()
+        notebook_contents = self.fspath.open(encoding='utf-8')
 
         with warnings.catch_warnings():
             warnings.filterwarnings("ignore", "IPython.core.inputsplitter is deprecated")
diff --git a/lbmpy_tests/phasefield/test_nphase_1D.py b/lbmpy_tests/phasefield/test_nphase_1D.py
index ce265386c35110c8ef985de28d68df390ef49f95..71359a97d27a4dffe33bf020220aa8cfe8e441cb 100644
--- a/lbmpy_tests/phasefield/test_nphase_1D.py
+++ b/lbmpy_tests/phasefield/test_nphase_1D.py
@@ -8,7 +8,6 @@ from lbmpy.phasefield.analytical import (
 from lbmpy.phasefield.experiments1D import init_sharp_interface
 from lbmpy.phasefield.scenarios import create_n_phase_model
 from pystencils import create_data_handling, make_slice
-from pystencils.runhelper import ParameterStudy
 
 
 def extract_profile(sc, width, phase_idx=1):
@@ -111,6 +110,7 @@ def study_1d(study):
 
 
 if __name__ == '__main__':
+    from pystencils.runhelper import ParameterStudy
     s = ParameterStudy(run_n_phase_1d)
     study_1d(s)
     s.run_from_command_line()
diff --git a/lbmpy_tests/phasefield/test_nphase_2D.py b/lbmpy_tests/phasefield/test_nphase_2D.py
index 7d4359d90a1e09ce3494ff5175cafc2393cec56e..0254c944649ec503a86fa2d6539c20c5f0e8aa5f 100644
--- a/lbmpy_tests/phasefield/test_nphase_2D.py
+++ b/lbmpy_tests/phasefield/test_nphase_2D.py
@@ -9,7 +9,6 @@ from lbmpy.phasefield.contact_angle_circle_fitting import liquid_lens_neumann_an
 from lbmpy.phasefield.post_processing import analytic_neumann_angles
 from lbmpy.phasefield.scenarios import create_n_phase_model, create_three_phase_model
 from pystencils import create_data_handling, make_slice
-from pystencils.runhelper import ParameterStudy
 from pystencils.utils import boolean_array_bounding_box
 
 color = {'yellow': '\033[93m',
@@ -209,6 +208,7 @@ def study_2d(study, **kwargs):
 
 
 def main():
+    from pystencils.runhelper import ParameterStudy
     s = ParameterStudy(run_n_phase_2d)
     # study_3phase(s)
     study_2d(s)