Fetch JSON into variable instead of file

tests/preprocessing_test.py

@@ -1,5 +1,3 @@
-from os import remove
-
 from pandas import DataFrame
 from requests import get
 
@@ -22,8 +20,6 @@ def test_dataframe_creation():
     Verifes that the DataFrames are created and filtered properly
     """
     for dataset in DATASETS:
-        request_dataset(dataset)
         df = create_dataframe(dataset)
-        remove(FILES[dataset])
         assert isinstance(df, DataFrame)
         assert all(df.columns == COLUMNS[dataset])