Fix pylint issues

scripts/isolate_tests.py

@@ -13,7 +13,8 @@ import hashlib
 from os.path import join, isfile, split
 
 def extract_test_cases(path):
-    lines = open(path, encoding="utf8", errors='ignore', mode='r', newline='').read().splitlines()
+    with open(path, encoding="utf8", errors='ignore', mode='r', newline='') as file:
+        lines = file.read().splitlines()
 
     inside = False
     delimiter = ''
@@ -45,7 +46,10 @@ def extract_docs_cases(path):
     tests = []
 
     # Collect all snippets of indented blocks
-    for l in open(path, mode='r', errors='ignore', encoding='utf8', newline='').read().splitlines():
+
+    with open(path, mode='r', errors='ignore', encoding='utf8', newline='') as f:
+        lines = f.read().splitlines()
+    for l in lines:
         if l != '':
             if not insideBlock and l.startswith(' '):
                 # start new test
@@ -87,14 +91,16 @@ def write_cases(f, tests):
         # so before checking remove 4 spaces from each line.
         remainder = re.sub(r'^ {4}', '', test, 0, re.MULTILINE)
         sol_filename = 'test_%s_%s.sol' % (hashlib.sha256(test.encode("utf-8")).hexdigest(), cleaned_filename)
-        open(sol_filename, mode='w', encoding='utf8', newline='').write(remainder)
+        with open(sol_filename, mode='w', encoding='utf8', newline='') as fi:
+            fi.write(remainder)
 
 def extract_and_write(f, path):
     if docs:
         cases = extract_docs_cases(path)
     else:
         if f.endswith('.sol'):
-            cases = [open(path, mode='r', encoding='utf8', newline='').read()]
+            with open(path, mode='r', encoding='utf8', newline='') as _f:
+                cases = [_f.read()]
         else:
             cases = extract_test_cases(path)
     write_cases(f, cases)