Alias_method_chain and ActiveSupport::TestCase

Rails
1

I’m trying to add some functionality to the setup method of all my
tests.

I added a method called setup_with_ts in the test_helper and chained
it using alias_method_chain :setup, :ts and that works great for every
test that does not define setup in the test.

So for my unit tests i tried also defining the same method
setup_with_ts in a
class ActiveSupport::TestCase
def setup_with_ts
puts “setup with ts”
setup_without_ts
end
alias_method_chain :setup, :ts
end

it was just a test to see what would happen.

if i called this method in the setup of a test like :
def setup
setup_with_ts
.
.
.
end

that will call it just fine so the method exists. but if i remove the
setup_with_ts line and run a test the setup method in the test runs,
but it never runs my aliased chained method.

i’m not sure why the alias_method_chain seems to work for test with no
setup method and not for one that has a setup method defined. Any
help would be great.

Thanks.
Erik

2

Just an update:

It is some kind of order of file loading or something.

If i put
def setup_with_ts
puts “setup with ts”
setup_without_ts
end
alias_method_chain :setup, :ts

that directly into a test with a setup method it works fine, but not
if i define it in the test_helper.rb

Erik

3

Another update:
if i do:
class ActiveSupport::TestCase
def setup_with_ts
puts “setup with ts”
setup_without_ts
end
alias_method_chain :setup, :ts
end

and then do puts self.methods in one of my tests it shows those
methods exist. but they do not get called unless i define
setup_with_ts and alias it in each test…

4

On Oct 21, 7:38 pm, erik [email protected] wrote:

i’m not sure why the alias_method_chain seems to work for test with no
setup method and not for one that has a setup method defined. Any
help would be great.

In a nutshell, because there is no reason it should. If a class
overrides the superclass implementation of a method then that
superclass implementation is not called unless the new implementation
explicitly does it. You should be able to do

def setup
super
…
end

However you don’t need to do all this, because ActiveSupport::TestCase
already handles this sort of stuff. If you do

class ActiveSupport::TestCase
def setup_with_ts
end

setup :setup_with_ts
end

then your method will get called at the appropriate time
(ActiveSupport sets up a callback chain that is run just before setup
is called)

Fred