unittest: assertRaises() with an instance instead of a type
tjreedy at udel.edu
Thu Mar 29 17:04:47 CEST 2012
On 3/29/2012 3:28 AM, Ulrich Eckhardt wrote:
>> Equality comparison is by id. So this code will not do what you want.
> >>> Exception('foo') == Exception('foo')
> Yikes! That was unexpected and completely changes my idea. Any clue
> whether this is intentional? Is identity the fallback when no equality
> is defined for two objects?
Yes. The Library Reference 4.3. Comparisons (for built-in classes) puts
is this way.
"Objects of different types, except different numeric types, never
compare equal. Furthermore, some types (for example, function objects)
support only a degenerate notion of comparison where any two objects of
that type are unequal." In other words, 'a==b' is the same as 'a is b'.
That is also the default for user-defined classes, but I am not sure
where that is documented, if at all.
Terry Jan Reedy
More information about the Python-list