Properly close opened files in three tests

pandas/io/tests/test_common.py

@@ -116,8 +116,8 @@ def test_constructor_bad_file(self):
         tm.assertRaisesRegexp(ValueError, msg, common.MMapWrapper, target)
 
     def test_get_attr(self):
-        target = open(self.mmap_file, 'r')
-        wrapper = common.MMapWrapper(target)
+        with open(self.mmap_file, 'r') as target:
+            wrapper = common.MMapWrapper(target)
 
         attrs = dir(wrapper.mmap)
         attrs = [attr for attr in attrs
@@ -130,10 +130,9 @@ def test_get_attr(self):
         self.assertFalse(hasattr(wrapper, 'foo'))
 
     def test_next(self):
-        target = open(self.mmap_file, 'r')
-        wrapper = common.MMapWrapper(target)
-
-        lines = target.readlines()
+        with open(self.mmap_file, 'r') as target:
+            wrapper = common.MMapWrapper(target)
+            lines = target.readlines()
 
         for line in lines:
             next_line = next(wrapper)

pandas/tests/series/test_io.py

@@ -64,7 +64,8 @@ def test_to_csv(self):
         with ensure_clean() as path:
             self.ts.to_csv(path)
 
-            lines = io.open(path, newline=None).readlines()
+            with io.open(path, newline=None) as f:
+                lines = f.readlines()
             assert (lines[1] != '\n')
 
             self.ts.to_csv(path, index=False)