Additional tests for seek() method, written by Trent Mick

Lib/test/test_mmap.py

@@ -58,7 +58,42 @@ def test_both():
         
         assert start == PAGESIZE
         assert end == PAGESIZE + 6
-        
+
+    # test seeking around (try to overflow the seek implementation)
+    m.seek(0,0)
+    print '  Seek to zeroth byte'
+    assert m.tell() == 0
+    m.seek(42,1)
+    print '  Seek to 42nd byte'
+    assert m.tell() == 42
+    m.seek(0,2)
+    print '  Seek to last byte'
+    assert m.tell() == len(m)
+	
+    print '  Try to seek to negative position...'
+    try:
+        m.seek(-1)
+    except ValueError:
+        pass
+    else:
+        assert 0, 'expected a ValueError but did not get it'
+
+    print '  Try to seek beyond end of mmap...'
+    try:
+        m.seek(1,2)
+    except ValueError:
+        pass
+    else:
+        assert 0, 'expected a ValueError but did not get it'
+
+    print '  Try to seek to negative position...'
+    try:
+        m.seek(-len(m)-1,2)
+    except ValueError:
+        pass
+    else:
+        assert 0, 'expected a ValueError but did not get it'
+
     m.close()
     os.unlink("foo")
     print ' Test passed'