Mock Global method

Testing RSpec
1

Hi All,

I’m very new to ruby and mocking a dynamic language. I would like to
mock a helper method in Sinatra. So an example is this:

helper do
def my_helper_method
puts “Should do something useful here…”
end
end

How would I mock that method and how would I mock a method in general
that is a global method. Is it better practice not to have global
methods? Should I rather have an object inside the method call that
does all the work and I can mock that?

Thanks

2

I’m actually looking to mock “my_helper_method” here. Or to be more
general any method that is created outside of a class.

On Mar 25, 6:27 am, “J. B. Rainsberger” [email protected]

3

On Mar 25, 2010, at 8:44 AM, garren wrote:

I’m actually looking to mock “my_helper_method” here. Or to be more
general any method that is created outside of a class.

When you create a method outside a class, it is available on every
object:

def foo
“foo”
end

class Bar
end

describe Bar do
it “responds to foo” do
Bar.new.foo.should == “foo”
end
end

In terms of mocking or stubbing that, just do it directly on the object.

describe Widget do
it “does something” do
widget = Widget.new
widget.stub(:some_method_i_defined_outside_a_class) { “this value” }
# …
end
end

HTH,
David

PS, if you’re mocking or stubbing a method, it doesn’t need to actually
exist.

4

Perfect thanks for that.

5

garren wrote:

How would I mock that method and how would I mock a method in general
that is a global method. Is it better practice not to have global
methods? Should I rather have an object inside the method call that
does all the work and I can mock that?

You can probably set an expectation on Kernel#puts, since although #puts
looks global, it belongs to Kernel.

As for whether you should use #puts directly here, or indirectly through
another object that you can easily control, that depends on the
situation. Try both and compare the results.

In your situation, I’d probably just set expectations on Kernel#puts
until that caused me problems, at which point I’d separate the behavior
of deciding what to print from deciding where to print it. I find
formatting messages much easier to check, in general, than displaying
them.

Have fun.