<s>
xUnit	B-Library
is	O
the	O
collective	O
name	O
for	O
several	O
unit	O
testing	O
frameworks	B-Architecture
that	O
derive	O
their	O
structure	O
and	O
functionality	O
from	O
Smalltalk	B-Application
's	O
SUnit	B-Library
.	O
</s>
<s>
SUnit	B-Library
,	O
designed	O
by	O
Kent	O
Beck	O
in	O
1998	O
,	O
was	O
written	O
in	O
a	O
highly	O
structured	O
object-oriented	B-Language
style	O
,	O
which	O
lent	O
easily	O
to	O
contemporary	O
languages	O
such	O
as	O
Java	B-Language
and	O
C#	B-Application
.	O
</s>
<s>
Following	O
its	O
introduction	O
in	O
Smalltalk	B-Application
the	O
framework	O
was	O
ported	O
to	O
Java	B-Language
by	O
Kent	O
Beck	O
and	O
Erich	O
Gamma	O
and	O
gained	O
wide	O
popularity	O
,	O
eventually	O
gaining	O
ground	O
in	O
the	O
majority	O
of	O
programming	O
languages	O
in	O
current	O
use	O
.	O
</s>
<s>
The	O
names	O
of	O
many	O
of	O
these	O
frameworks	B-Architecture
are	O
a	O
variation	O
on	O
"	O
SUnit	B-Library
"	O
,	O
usually	O
replacing	O
the	O
"	O
S	O
"	O
with	O
the	O
first	O
letter	O
(	O
or	O
letters	O
)	O
in	O
the	O
name	O
of	O
their	O
intended	O
language	O
(	O
"	O
JUnit	B-Language
"	O
for	O
Java	B-Language
,	O
"	O
RUnit	B-Device
"	O
for	O
R	B-Language
etc	O
.	O
)	O
.	O
</s>
<s>
These	O
frameworks	B-Architecture
and	O
their	O
common	O
architecture	O
are	O
collectively	O
known	O
as	O
"	O
xUnit	B-Library
"	O
.	O
</s>
<s>
All	O
xUnit	B-Library
frameworks	B-Architecture
share	O
the	O
following	O
basic	O
component	O
architecture	O
,	O
with	O
some	O
varied	O
implementation	O
details	O
.	O
</s>
<s>
A	O
test	O
runner	O
is	O
an	O
executable	O
program	O
that	O
runs	O
tests	O
implemented	O
using	O
an	O
xUnit	B-Library
framework	O
and	O
reports	O
the	O
test	O
results	O
.	O
</s>
<s>
In	O
addition	O
to	O
a	O
plain	O
,	O
human-readable	O
format	O
,	O
there	O
is	O
often	O
a	O
test	O
result	O
formatter	O
that	O
produces	O
XML	B-Protocol
output	O
.	O
</s>
<s>
The	O
XML	B-Protocol
test	O
result	O
format	O
originated	O
with	O
JUnit	B-Language
but	O
is	O
also	O
used	O
by	O
some	O
other	O
xUnit	B-Library
testing	O
frameworks	B-Architecture
,	O
for	O
instance	O
build	O
tools	O
such	O
as	O
Jenkins	B-Language
and	O
Atlassian	O
Bamboo	O
.	O
</s>
<s>
Failure	O
of	O
an	O
assertion	O
typically	O
throws	O
an	O
exception	B-General_Concept
,	O
aborting	O
the	O
execution	O
of	O
the	O
current	O
test	O
.	O
</s>
<s>
Many	O
xUnit	B-Library
frameworks	B-Architecture
exist	O
for	O
various	O
programming	O
languages	O
and	O
development	O
platforms	O
.	O
</s>
