def test_separate():
'''
Two fields not touching
'''
field1 = (1, 1, 2, 2)
field2 = (3, 3, 4, 4)
assert overlap_area(field1, field2) == 0
def test_corner_touch():
'''
Two fields with a single corner touching
'''
field1 = (1, 1, 2, 2)
field2 = (2, 2, 3, 3)
assert overlap_area(field1, field2) == 0
def test_outside_touch():
'''
Two fields, one outside the other,
touching on one side, no overlap.
'''
field1 = (1, 1, 4, 2)
field2 = (2, 2, 3, 3)
assert overlap_area(field1, field2) == 0
def test_inside_touch():
'''
Two fields, one inside the other,
touching on one side..
'''
field1 = (1, 1, 4, 4)
field2 = (2, 3, 3, 4)
assert overlap_area(field1, field2) == 1
def test_corners_overlap():
'''
Two fields with only a corner of each overlapping.
Use non-integer values
'''
field1 = (1, 1, 4.5, 3.5)
field2 = (2, 2, 2.8, 3.9)
assert overlap_area(field1, field2) == approx(1.19999, rel=1e-3)
def test_entirely_inside_not_touch():
'''
Tests that basic example works. One field is entirely inside
the other with no sides touching.
'''
big_field = (1, 1, 4, 4)
inner_field = (2, 2, 3, 3)
assert overlap_area(big_field, inner_field) == 1