specify encoding to open file

test_notebooks.py

@@ -25,6 +25,11 @@
 
 SI = pint.UnitRegistry()
 
+COLAB_HEADER = """import sys
+if 'google.colab' in sys.modules:
+    !pip --quiet install open-atmos-jupyter-utils
+    from open_atmos_jupyter_utils import pip_install_on_colab
+    pip_install_on_colab('PySDM-examples')"""
 
 @pytest.fixture(
     params=find_files(file_extension=".ipynb"),
@@ -83,13 +88,6 @@ def test_jetbrains_bug_py_66491(notebook_filename):
                     + " (could be due to a bug in PyCharm,"
                     + " see https://youtrack.jetbrains.com/issue/PY-66491 )"
                 )
-
-
-COLAB_HEADER = """import sys
-if 'google.colab' in sys.modules:
-    !pip --quiet install open-atmos-jupyter-utils
-    from open_atmos_jupyter_utils import pip_install_on_colab
-    pip_install_on_colab('PySDM-examples')"""
 
 def _relative_path(absolute_path):
     return os.path.relpath(
@@ -114,7 +112,7 @@ def _colab_badge_markdown(absolute_path):
 
 def test_first_cell_contains_three_badges(notebook):
     """ checks if all notebooks feature nbviewer, mybinder and Colab badges (in the first cell) """
-    with open(notebook) as fp:
+    with open(notebook, encoding="utf8") as fp:
         nb = nbformat.read(fp, nbformat.NO_CONVERT)
         assert len(nb.cells) > 0
         assert nb.cells[0].cell_type == "markdown"
@@ -127,15 +125,15 @@ def test_first_cell_contains_three_badges(notebook):
 
 def test_second_cell_is_a_markdown_cell(notebook):
     """ checks if all notebooks have their second cell with some markdown (hopefully clarifying what the example is about) """
-    with open(notebook) as fp:
+    with open(notebook, encoding="utf8") as fp:
         nb = nbformat.read(fp, nbformat.NO_CONVERT)
         assert len(nb.cells) > 1
         assert nb.cells[1].cell_type == "markdown"
 
 
 def test_third_cell_contains_colab_header(notebook):
     """ checks if all notebooks feature a Colab-magic cell """
-    with open(notebook) as fp:
+    with open(notebook, encoding="utf8") as fp:
         nb = nbformat.read(fp, nbformat.NO_CONVERT)
         assert len(nb.cells) > 2
         assert nb.cells[2].cell_type == "code"