NA Removed from Otter Grade CSV tests

test/test_grade/test_integration.py

@@ -89,8 +89,8 @@ def test_timeout_some_notebooks_finish():
         containers = 5,
         timeout = grade_timeout,
     )
-    df_test = pd.read_csv("test/final_grades.csv", na_values='--')
-    assert pd.isna(df_test.iloc[0]["grading_status"])
+    df_test = pd.read_csv("test/final_grades.csv")
+    assert df_test.iloc[0]["grading_status"] == "--"
     assert df_test.iloc[1]["grading_status"] == "Completed"
     pattern = rf"Executing '[\w.\/-]*test\/test_grade\/files\/timeout\/1min\.ipynb' in docker container timed out in {grade_timeout} seconds"
     assert re.match(pattern, df_test.iloc[2]["grading_status"]) is not None
@@ -112,7 +112,7 @@ def test_timeout_no_notebooks_finish():
         containers = 5,
         timeout = grade_timeout,
     )
-    df_test = pd.read_csv("test/final_grades.csv", na_values='--')
+    df_test = pd.read_csv("test/final_grades.csv")
     pattern1min = rf"Executing '[\w.\/-]*test\/test_grade\/files\/timeout\/1min\.ipynb' in docker container timed out in {grade_timeout} seconds"
     pattern10s = rf"Executing '[\w.\/-]*test\/test_grade\/files\/timeout\/10s\.ipynb' in docker container timed out in {grade_timeout} seconds"
     assert re.match(pattern10s, df_test.iloc[0]["grading_status"]) is not None
@@ -135,7 +135,7 @@ def test_network(expected_points):
         no_network = True,
     )
 
-    df_test = pd.read_csv("test/final_grades.csv", na_values='--')
+    df_test = pd.read_csv("test/final_grades.csv")
 
     # sort by filename
     df_test = df_test.sort_values("file").reset_index(drop=True)
@@ -164,7 +164,7 @@ def test_notebooks_with_pdfs(expected_points):
     )
 
     # read the output and expected output
-    df_test = pd.read_csv("test/final_grades.csv", na_values='--')
+    df_test = pd.read_csv("test/final_grades.csv")
 
     # sort by filename
     df_test = df_test.sort_values("file").reset_index(drop=True)