Why does this (not) work?

[Michael C. Neel]

I've got this string in which I need to sub in the same word several
times; i.e:

"%s - %s - %s" % ("test","test","test") 'test - test - test'
But I want to use the * to make life easier to read, so I tried:
("test",)*3 ('test', 'test', 'test') "%s - %s - %s" % ("test",)*3 Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: not enough arguments for format string
Which seemed like a good idea, but after some playing around I found
that:
eval(str(("test",)*3)) ('test', 'test', 'test') "%s - %s - %s" % eval(str(("test",)*3)) 'test - test - test'
Did work. Odd because:
type(("test",)*3) <type 'tuple'> type(eval(str(("test",)*3))) <type 'tuple'>

Any idea why the tuple to str to tuple works and not the tuple straight?

Mike