def test_str_expr_replacement(self):
# Signature: name(cls, frm, to, expr_string, func_ok=False)
# replaces all occurences of name 'frm' with 'to' in expr_string
# ('frm' may not occur as a function name on the rhs) ...
# 'to' can be an arbitrary string so this function can also be used for
# argument substitution.
#
# Returns the resulting string.
# from nineml.abstraction_layer.component.util import MathUtil
t = 'b*c + d/(e*sin(f+g/e)) + b1 + e_ / exp(12*g)'
t = MathUtil.str_expr_replacement('b', 'B', t)
self.assertEqual(t, 'B*c + d/(e*sin(f+g/e)) + b1 + e_ / exp(12*g)')
# 'e' is a builtin, so this function doesn't care.
t = MathUtil.str_expr_replacement(frm='e', to='E', expr_string=t)
self.assertEqual(t, 'B*c + d/(E*sin(f+g/E)) + b1 + e_ / exp(12*g)')
