test_parser
Expressions:
foo(1)
[1, 2, 3]
[x**3 for x in range(20)]
[x**3 for x in range(20) if x % 3]
foo(*args)
foo(*args, **kw)
foo(**kw)
foo(key=value)
foo(key=value, *args)
foo(key=value, *args, **kw)
foo(key=value, **kw)
foo(a, b, c, *args)
foo(a, b, c, *args, **kw)
foo(a, b, c, **kw)
foo + bar

Statements:
print
print 1
print 1,
print >>fp
print >>fp, 1
print >>fp, 1,

Invalid parse trees:

<junk>
caught expected exception for invalid tree

print >>fp,
caught expected exception for invalid tree

a,,c
caught expected exception for invalid tree