<s>
QuickCheck	B-Application
is	O
a	O
software	B-Library
library	I-Library
,	O
specifically	O
a	O
combinator	B-Library
library	I-Library
,	O
originally	O
written	O
in	O
the	O
programming	O
language	O
Haskell	B-Language
,	O
designed	O
to	O
assist	O
in	O
software	O
testing	O
by	O
generating	O
test	O
cases	O
for	O
test	O
suites	O
–	O
an	O
approach	O
known	O
as	O
property	O
testing	O
.	O
</s>
<s>
It	O
is	O
compatible	O
with	O
the	O
compiler	B-Language
,	O
Glasgow	B-Application
Haskell	I-Application
Compiler	I-Application
(	O
GHC	O
)	O
and	O
the	O
interpreter	B-Application
,	O
Haskell	B-Language
User	O
's	O
Gofer	O
System	O
(	O
Hugs	B-Application
)	O
.	O
</s>
<s>
It	O
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
released	O
under	O
a	O
BSD-style	B-Operating_System
license	I-Operating_System
.	O
</s>
<s>
In	O
QuickCheck	B-Application
,	O
assertions	O
are	O
written	O
about	O
logical	O
properties	O
that	O
a	O
function	O
should	O
fulfill	O
.	O
</s>
<s>
Then	O
QuickCheck	B-Application
attempts	O
to	O
generate	O
a	O
test	O
case	O
that	O
falsifies	O
such	O
assertions	O
.	O
</s>
<s>
Once	O
such	O
a	O
test	O
case	O
is	O
found	O
,	O
QuickCheck	B-Application
tries	O
to	O
reduce	O
it	O
to	O
a	O
minimal	O
failing	O
subset	O
by	O
removing	O
or	O
simplifying	O
input	O
data	O
that	O
are	O
unneeded	O
to	O
make	O
the	O
test	O
fail	O
.	O
</s>
<s>
Besides	O
being	O
used	O
to	O
test	O
regular	O
programs	O
,	O
QuickCheck	B-Application
is	O
also	O
useful	O
for	O
building	O
up	O
a	O
functional	O
specification	O
,	O
for	O
documenting	O
what	O
functions	O
should	O
be	O
doing	O
,	O
and	O
for	O
testing	O
compiler	B-Language
implementations	O
.	O
</s>
<s>
Re-implementations	O
of	O
QuickCheck	B-Application
exist	O
for	O
several	O
languages	O
:	O
</s>
