def test_variable_replacement(): """Test replace variables by values and symbols in expression.""" expr = demo_fall vdict = Variable.__defaults__.copy() vdict[Symbol('x')] = 1 assert replace_variables(expr, vdict) == \ Eq(demo_d, 4.9 * demo_fall.definition.t ** 2)
def test_substitution(): """Test if .subs() method gives the same result as replace_variables.""" assert demo_fall.subs(demo_d, demo_d1) == \ replace_variables(demo_fall, {demo_d: demo_d1})