def test_diofantissue_376():
f = symbols('f', cls=Function)
e1 = Subs(Derivative(f(x), x), (x, y*z))
e2 = Subs(Derivative(f(t), t), (t, y*z))
assert (x*e1).subs({e2: y}) == x*y
e3 = Subs(Derivative(f(t), t), (t, y*z**2))
assert e3.subs({e2: y}) == e3
e4 = Subs(Derivative(f(t), t, t), (t, y*z))
assert e4.subs({e2: y}) == e4
def test_diofantissue_376():
f = symbols('f', cls=Function)
e1 = Subs(Derivative(f(x), x), (x, y * z))
e2 = Subs(Derivative(f(t), t), (t, y * z))
assert (x * e1).subs({e2: y}) == x * y
e3 = Subs(Derivative(f(t), t), (t, y * z**2))
assert e3.subs({e2: y}) == e3
e4 = Subs(Derivative(f(t), t, t), (t, y * z))
assert e4.subs({e2: y}) == e4
def test_diofantissue_376():
x, y, z, t = symbols('x y z t')
f = symbols('f', cls=Function)
e1 = Subs(Derivative(f(x), x), x, y * z)
e2 = Subs(Derivative(f(t), t), t, y * z)
assert (x * e1).subs(e2, y) == x * y
e3 = Subs(Derivative(f(t), t), t, y * z**2)
assert e3.subs(e2, y) == e3
e4 = Subs(Derivative(f(t), t, t), t, y * z)
assert e4.subs(e2, y) == e4