Given /^(\w+) = (\w+)$/ do |var, value|
  instance_variable_set("@#{var}", value)
end

Then /^I can assert that (\w+).assert == (\w+)$/ do |var_a, var_b|
  a = instance_variable_get("@#{var_a}")
  b = instance_variable_get("@#{var_b}")
  a.assert == b
end