diff --git a/test/decompyle/test_global.py b/test/decompyle/test_global.py
index c789eb84..7a042854 100644
--- a/test/decompyle/test_global.py
+++ b/test/decompyle/test_global.py
@@ -14,11 +14,11 @@ def a():
         def c():
             k = 34
             global i
-            i = i+k
+            i += k
         l = 42
         c()
         global j
-        j = j+l
+        j += l
     b()
     print i, j # should print 35, 49
 
diff --git a/test/decompyle/test_globals.py b/test/decompyle/test_globals.py
index 6e9cad01..46aec930 100644
--- a/test/decompyle/test_globals.py
+++ b/test/decompyle/test_globals.py
@@ -8,7 +8,7 @@
 
 def f():
     print x  # would result in a 'NameError' or 'UnboundLocalError'
-    x = x+1
+    x += 1
     print x
 
 raise "This program can't be run"
diff --git a/test/decompyle/test_loops.py b/test/decompyle/test_loops.py
index c5e11b5b..1b200241 100644
--- a/test/decompyle/test_loops.py
+++ b/test/decompyle/test_loops.py
@@ -28,7 +28,7 @@ else:
 
 i = 0
 while i < 10:
-    i = i+1
+    i += 1
     if i == 3:
         continue
     if i == 5:
@@ -40,7 +40,7 @@ print
 
 i = 0
 while i < 10:
-    i = i+1
+    i += 1
     if i == 3:
         continue
     print i,
diff --git a/test/ok_lib2.7/bsddb/dbrecio.py b/test/ok_lib2.7/bsddb/dbrecio.py
index d439f325..46324cbf 100644
--- a/test/ok_lib2.7/bsddb/dbrecio.py
+++ b/test/ok_lib2.7/bsddb/dbrecio.py
@@ -55,9 +55,9 @@ class DBRecIO:
         if self.closed:
             raise ValueError, "I/O operation on closed file"
         if mode == 1:
-            pos = pos + self.pos
+            pos += self.pos
         elif mode == 2:
-            pos = pos + self.len
+            pos += self.len
         self.pos = max(0, pos)
 
     def tell(self):
@@ -84,7 +84,7 @@ class DBRecIO:
         if self.closed:
             raise ValueError, "I/O operation on closed file"
         if self.buflist:
-            self.buf = self.buf + string.joinfields(self.buflist, '')
+            self.buf += string.joinfields(self.buflist, '')
             self.buflist = []
         i = string.find(self.buf, '\n', self.pos)
         if i < 0:
diff --git a/test/ok_lib2.7/compiler/misc.py b/test/ok_lib2.7/compiler/misc.py
index 588c7fbd..d476564f 100644
--- a/test/ok_lib2.7/compiler/misc.py
+++ b/test/ok_lib2.7/compiler/misc.py
@@ -3,7 +3,7 @@ def flatten(tup):
     elts = []
     for elt in tup:
         if isinstance(elt, tuple):
-            elts = elts + flatten(elt)
+            elts += flatten(elt)
         else:
             elts.append(elt)
     return elts
@@ -53,7 +53,7 @@ def mangle(name, klass):
     try:
         i = 0
         while klass[i] == '_':
-            i = i + 1
+            i += 1
     except IndexError:
         return name
     klass = klass[i:]
diff --git a/test/ok_lib2.7/compiler/syntax.py b/test/ok_lib2.7/compiler/syntax.py
index a45d9c2c..c54e1b8e 100644
--- a/test/ok_lib2.7/compiler/syntax.py
+++ b/test/ok_lib2.7/compiler/syntax.py
@@ -30,7 +30,7 @@ class SyntaxErrorChecker:
         self.errors = 0
 
     def error(self, node, msg):
-        self.errors = self.errors + 1
+        self.errors += 1
         if self.multi is not None:
             print "%s:%s: %s" % (node.filename, node.lineno, msg)
         else:
diff --git a/test/simple_source/bug30/04_and_del.py b/test/simple_source/bug30/04_and_del.py
index b161026f..64b4aa4a 100644
--- a/test/simple_source/bug30/04_and_del.py
+++ b/test/simple_source/bug30/04_and_del.py
@@ -9,11 +9,11 @@ def normpath(comps):
             del comps[i]
         elif comps[i] == '..' and i > 0 and comps[i-1] not in ('', '..'):
             del comps[i-1:i+1]
-            i = i - 1
+            i -= 1
         elif comps[i] == '' and i > 0 and comps[i-1] != '':
             del comps[i]
         else:
-            i = i + 1
+            i += 1
     return comps
 
 assert normpath(['.']) == []
diff --git a/test/simple_source/bug36/09_ext_arg_jump.py b/test/simple_source/bug36/09_ext_arg_jump.py
index d14cc98a..b18cc1a3 100644
--- a/test/simple_source/bug36/09_ext_arg_jump.py
+++ b/test/simple_source/bug36/09_ext_arg_jump.py
@@ -2,7 +2,7 @@
 # messing up control flow detection
 def _format_usage(self, usage, actions, groups, prefix):
     if usage:
-        usage = usage % dict(prog=self._prog)
+        usage %= dict(prog=self._prog)
 
     elif usage is None:
         prog = 5