Subset Fixture compares an actual collection of objects to its table of expected values. It is the same as
Array Fixture, except surplus objects in the actual collection are ignored, and order is not significant.
setup sample array 
column a  column b 
a  x 
a  y 
b  y 
Matching cells are marked.
when test is⇓
story test fixture 
check  test result 
sample subset 
column a  column b 
a  x 
a  y 
b  y 

sample subset 
column a  column b 
a  x 
a  y 
b  y 


sample subset 
column a  column b 
a  x 
a  y 
b  y 
 then result is 
sample subset 
column a  column b 
a  x 
a  y 
b  y 

Surplus rows and order are ignored.
when test is⇓
story test fixture 
check  test result 
sample subset 
column a  column b 
b  y 
a  x 

sample subset 
column a  column b 
b  y 
a  x 


sample subset 
column a  column b 
b  y 
a  x 
 then result is 
sample subset 
column a  column b 
b  y 
a  x 

Mismatched cells and missing rows are reported.
when test is⇓
story test fixture 
check  test result 
sample subset 
column a  column b 
n  o 
b  z 

sample subset 
column a  column b 
n missing  o 
b  z expected y actual At 0 expected z was y 


sample subset 
column a  column b 
n  o 
b  z 
 then result is 
sample subset 
column a  column b 
n missing  o 
b  z expected y actual At 0 expected z was y 
