<s>
A	O
decision-to-decision	B-General_Concept
path	I-General_Concept
,	O
or	O
DD-path	B-General_Concept
,	O
is	O
a	O
path	O
of	O
execution	O
(	O
usually	O
through	O
a	O
flow	O
graph	O
representing	O
a	O
program	O
,	O
such	O
as	O
a	O
flow	B-Language
chart	I-Language
)	O
between	O
two	O
decisions	O
.	O
</s>
<s>
More	O
recent	O
versions	O
of	O
the	O
concept	O
also	O
include	O
the	O
decisions	O
themselves	O
in	O
their	O
own	O
DD-paths	B-General_Concept
.	O
</s>
<s>
In	O
Huang	O
's	O
1975	O
paper	O
,	O
a	O
decision-to-decision	B-General_Concept
path	I-General_Concept
is	O
defined	O
as	O
path	O
in	O
a	O
program	O
's	O
flowchart	B-Language
such	O
that	O
all	O
the	O
following	O
hold	O
(	O
quoting	O
from	O
the	O
paper	O
)	O
:	O
</s>
<s>
A	O
DD-path	B-General_Concept
is	O
a	O
set	O
of	O
nodes	O
in	O
a	O
program	O
graph	O
such	O
that	O
one	O
of	O
the	O
following	O
holds	O
(	O
quoting	O
and	O
keeping	O
Jorgensen	O
's	O
numbering	O
,	O
with	O
comments	O
added	O
in	O
parenthesis	O
)	O
:	O
</s>
<s>
Every	O
node	O
on	O
a	O
flow	O
graph	O
of	O
a	O
program	O
belongs	O
to	O
one	O
DD-path	B-General_Concept
.	O
</s>
<s>
If	O
the	O
first	O
node	O
on	O
a	O
DD-path	B-General_Concept
is	O
traversed	O
,	O
then	O
all	O
other	O
nodes	O
on	O
that	O
path	O
will	O
also	O
be	O
traversed	O
.	O
</s>
<s>
The	O
DD	B-General_Concept
path	I-General_Concept
graph	O
is	O
used	O
to	O
find	O
independent	O
path	O
for	O
testing	O
.	O
</s>
<s>
According	O
to	O
Jorgensen	O
's	O
2013	O
textbook	O
,	O
DD-path	B-General_Concept
testing	O
is	O
the	O
best	O
known	O
code-based	O
testing	O
method	O
,	O
incorporated	O
in	O
numerous	O
commercial	O
tools	O
.	O
</s>
<s>
DD-path	B-General_Concept
testing	O
is	O
also	O
called	O
C2	O
testing	O
or	O
branch	B-Application
coverage	I-Application
.	O
</s>
