Module: Test::Unit::Assertions

assert_difference(expressions, difference = 1, message = nil) {|| ...} Test numeric difference between the return value of an expression as a result of what is evaluated in the yielded block. assert_difference 'Article.count' do post :create, :article => {...} end An arbitrary expression is passed in and evaluated. assert_difference 'assigns(:article).comments(:reload).size' do post :create, :comm