def test_timeintervaltools_TimeInterval_shift_by_rational_01():
r'''TimeInterval.shift_by_rational returns a new TimeInterval instance unless offset is zero.
'''
i1 = TimeInterval(3, 23)
i2 = i1.shift_by_rational(1)
assert i1 != i2
i2 = i1.shift_by_rational(0)
assert i1 == i2
def test_timeintervaltools_TimeInterval_shift_by_rational_03():
r'''TimeIntervals can be shifted by fractions.
'''
i1 = TimeInterval(3, 23)
i2 = i1.shift_by_rational(Fraction(1, 5))
assert i2.start_offset == Fraction(16, 5)
assert i2.duration == i1.duration
def test_timeintervaltools_TimeInterval_shift_by_rational_02():
r'''TimeIntervals can be shifted by ints.
'''
i1 = TimeInterval(3, 23)
i2 = i1.shift_by_rational(2)
assert i2.start_offset == 5
assert i2.duration == i1.duration
