def test_derivative_subs3():
x = Symbol('x')
dex = Derivative(exp(x), x)
assert Derivative(dex, x).subs({dex: exp(x)}) == dex
assert dex.subs({exp(x): dex}) == Derivative(exp(x), x, x)
def test_deriv_sub_bug3():
y = Symbol('y')
f = Function('f')
pat = Derivative(f(x), x, x)
assert pat.subs({y: y**2}) == Derivative(f(x), x, x)
assert pat.subs({y: y**2}) != Derivative(f(x), x)
def test_derivative_subs3():
x = Symbol('x')
dex = Derivative(exp(x), x)
assert Derivative(dex, x).subs({dex: exp(x)}) == dex
assert dex.subs({exp(x): dex}) == Derivative(exp(x), x, x)
def test_derivative_subs3():
x = Symbol('x')
dex = Derivative(exp(x), x)
assert Derivative(dex, x).subs(dex, exp(x)) == dex
assert dex.subs(exp(x), dex) == Derivative(exp(x), x, x)
def test_deriv_sub_bug3():
y = Symbol('y')
f = Function('f')
pat = Derivative(f(x), x, x)
assert pat.subs({y: y**2}) == Derivative(f(x), x, x)
assert pat.subs({y: y**2}) != Derivative(f(x), x)
