Testing which RuntimeError is raised

Rails
1

I am just starting to use unit testing. Way cool. But I am not finding
very clear docs on assert_raise. I have managed to write a test that
tells me that the destroy I am trying to test fails with a
RuntimeError (as it should). However, I would really like to test that
it rails for the specific reason I have in my model. How can I get
more specific? Am I going to have to create my own exception class so
I have a named exception to check for? What I have a the moment is:

In my model file:

don’t destroy the home page (id = 1)

before_destroy :dont_destroy_homepage

def dont_destroy_homepage
raise “You can’t delete the home page or you will get rid of your
entire site” if id == 1
end

Then in my test file:

def test_cant_destroy_homepage
homepage = pages(:homepage)
assert_equal homepage.id, 1
# I would really love to figure out how to test what RuntimeError is
raised
assert_raise(RuntimeError) {homepage.destroy}
end

2

exception = assert_raise(RuntimeError) {homepage.destroy}
puts exception.message

(I think)

Chris

3

On 7/18/06, Chris R. [email protected] wrote:

exception = assert_raise(RuntimeError) {homepage.destroy}
puts exception.message

Thanks Chris. That does indeed print the message to the console - and
told me how to access the message. I altered my test to then assert
the message was what I wanted:

def test_cant_destroy_homepage
homepage = pages(:homepage)
assert_equal homepage.id, 1
problem = assert_raise(RuntimeError) {homepage.destroy}
assert_equal “You can’t delete the home page”, problem.message
end

And I was please to note that the assert_raise still counted in my
number of assertions.