unlink() would normally be found in the "os" module, so use it from there.

Remove unused import of "sys".

If the file TESTFN exists before we start, try to remove it.

Add spaces around the = in some assignments.

Lib/test/test_mmap.py

-from test_support import verify, TESTFN, unlink
+from test_support import verify, TESTFN
 import mmap
-import os, re, sys
+import os, re
 
 PAGESIZE = mmap.PAGESIZE
 
@@ -8,6 +8,8 @@ def test_both():
     "Test mmap module on Unix systems and Windows"
 
     # Create a file to be mmap'ed.
+    if os.path.exists(TESTFN):
+        os.unlink(TESTFN)
     f = open(TESTFN, 'w+')
 
     try:    # unlink TESTFN no matter what
@@ -36,7 +38,7 @@ def test_both():
         # Modify the file's content
         print "\n  Modifying file's content..."
         m[0] = '3'
-        m[PAGESIZE +3: PAGESIZE +3+3]='bar'
+        m[PAGESIZE +3: PAGESIZE +3+3] = 'bar'
 
         # Check that the modification worked
         print '  Contents of byte 0:', repr(m[0])
@@ -49,7 +51,7 @@ def test_both():
         m.flush()
 
         # Test doing a regular expression match in an mmap'ed file
-        match=re.search('[A-Za-z]+', m)
+        match = re.search('[A-Za-z]+', m)
         if match is None:
             print '  ERROR: regex match on mmap failed!'
         else:
@@ -126,7 +128,7 @@ def test_both():
         except OSError:
             pass
         try:
-            unlink(TESTFN)
+            os.unlink(TESTFN)
         except OSError:
             pass