1..6
# 2011-01-01T12:00:00
# 2011-01-01T13:00:00
ok 1 - Span intersects $dt1
ok 2 - Span doesn't intersects $dt2
ok 3 - Duration is 1 hour
# 2011-01-01T12:00:00
# 2011-01-01T13:00:00
ok 4 - Span intersects $dt1
ok 5 - Span doesn't intersects $dt2
ok 6 - Duration is 1 hour