def test_interactions(self):
f = formula.interactions([formula.Term(l) for l in ['a', 'b', 'c']])
assert_equal(set(f.termnames()),
set(['a', 'b', 'c', 'a*b', 'a*c', 'b*c']))
f = formula.interactions(
[formula.Term(l) for l in ['a', 'b', 'c', 'd']], order=3)
assert_equal(
set(f.termnames()),
set([
'a', 'b', 'c', 'd', 'a*b', 'a*c', 'a*d', 'b*c', 'b*d', 'c*d',
'a*b*c', 'a*c*d', 'a*b*d', 'b*c*d'
]))
f = formula.interactions(
[formula.Term(l) for l in ['a', 'b', 'c', 'd']], order=[1, 2, 3])
assert_equal(
set(f.termnames()),
set([
'a', 'b', 'c', 'd', 'a*b', 'a*c', 'a*d', 'b*c', 'b*d', 'c*d',
'a*b*c', 'a*c*d', 'a*b*d', 'b*c*d'
]))
f = formula.interactions(
[formula.Term(l) for l in ['a', 'b', 'c', 'd']], order=[3])
assert_equal(set(f.termnames()),
set(['a*b*c', 'a*c*d', 'a*b*d', 'b*c*d']))
def test_subtract(self):
f = formula.interactions([formula.Term(l) for l in ['a', 'b', 'c']])
ff = f - f['a*b']
assert_equal(set(ff.termnames()), set(['a', 'b', 'c', 'a*c', 'b*c']))
ff = f - f['a*b'] - f['a*c']
assert_equal(set(ff.termnames()), set(['a', 'b', 'c', 'b*c']))
ff = f - (f['a*b'] + f['a*c'])
assert_equal(set(ff.termnames()), set(['a', 'b', 'c', 'b*c']))
