rspec users - Apr 2007 - getting output of STDOUT in spec

Consider the following method:

def name_to_terminal
   puts "Scott Taylor"
end

How would I spec this out?

Scott

On 4/10/07, Scott Taylor <mailing_lists at railsnewbie.com>
wrote:
>
> Consider the following method:
>
> def name_to_terminal
>    puts "Scott Taylor"
> end
>
> How would I spec this out?
>
def name_to_terminal(io=STDOUT)
  io.puts "Scott Taylor"
end

then call it from a spec passing in a mock for io with the appropriate
expectation

> Scott
>
>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

On 4/10/07, Scott Taylor <mailing_lists at railsnewbie.com>
wrote:
>
> Consider the following method:
>
> def name_to_terminal
>    puts "Scott Taylor"
> end
>
> How would I spec this out?
RSpec prints to STDOUT, but the examples and implementation use an
instance of IO (mocked for the examples). So you''d have something
like:

describe Interactor do
  setup { @interactor = Interactor.new(@io = mock("IO")) }
  it "should print name to IO" do
    @io.should_receive(:<<).with("Scott Taylor")
    @interactor.print "Scott Taylor"
  end
end
>
> Scott
>
>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

On 10 Apr 2007, at 13:21, aslak hellesoy wrote:
> def name_to_terminal(io=STDOUT)
>   io.puts "Scott Taylor"
> end
>
> then call it from a spec passing in a mock for io with the appropriate
> expectation
Aha - this gives me an idea about the dreaded "current-time" problem

def do_something(time_factory=Time)
   time = time_factory.new
   # ...
end

Actually I suppose it works for any class.  Why didn''t I think of  
that before?  It''s so simple!

This is a variant of the dependency injection principle. It goes hand
in hand with mocking. I recommend martin fowler''s DI article for more
info.

On 4/10/07, Ashley Moran <work at ashleymoran.me.uk>
wrote:
>
> On 10 Apr 2007, at 13:21, aslak hellesoy wrote:
>
> > def name_to_terminal(io=STDOUT)
> >   io.puts "Scott Taylor"
> > end
> >
> > then call it from a spec passing in a mock for io with the appropriate
> > expectation
>
> Aha - this gives me an idea about the dreaded "current-time"
problem
>
> def do_something(time_factory=Time)
>    time = time_factory.new
>    # ...
> end
>
> Actually I suppose it works for any class.  Why didn''t I think of
> that before?  It''s so simple!
>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

There is one potential pitfall w/ this approach. I still use it in
spite of the pitfall, but it''s something you should be aware of.
It''s
entirely possible to default to the wrong this:

class NotTime
  class << self
    def now
      return ''or later''
    end
  end
end

class Thing do
  def do_something(time_factory=NotTime)
    time = time_factory.now
    ...
  end
end

If your examples always use mocks, and never challenge the assumption
that the default is Time, you can get into trouble.

In truth, I can''t recall when this has bitten me. But it does seem
like a hole you can fall in.

On 4/10/07, aslak hellesoy <aslak.hellesoy at gmail.com>
wrote:
> This is a variant of the dependency injection principle. It goes hand
> in hand with mocking. I recommend martin fowler''s DI article for
more
> info.
>
> On 4/10/07, Ashley Moran <work at ashleymoran.me.uk> wrote:
> >
> > On 10 Apr 2007, at 13:21, aslak hellesoy wrote:
> >
> > > def name_to_terminal(io=STDOUT)
> > >   io.puts "Scott Taylor"
> > > end
> > >
> > > then call it from a spec passing in a mock for io with the
appropriate
> > > expectation
> >
> > Aha - this gives me an idea about the dreaded "current-time"
problem
> >
> > def do_something(time_factory=Time)
> >    time = time_factory.new
> >    # ...
> > end
> >
> > Actually I suppose it works for any class.  Why didn''t I
think of
> > that before?  It''s so simple!
> >
> > _______________________________________________
> > rspec-users mailing list
> > rspec-users at rubyforge.org
> > http://rubyforge.org/mailman/listinfo/rspec-users
> >
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

On 11/04/2007, at 1:23 AM, Ashley Moran wrote:
> Aha - this gives me an idea about the dreaded "current-time"
problem
>
> def do_something(time_factory=Time)
>    time = time_factory.new
>    # ...
> end
>
> Actually I suppose it works for any class.  Why didn''t I think of
> that before?  It''s so simple!
Usually I just have "today" or "now" as a parameter:

def do_something(now=Time.now)
   # ...
end

def do_something(today=Date.today)
   # ...
end

Though there''s no reason you couldn''t mock those two method
calls...

-- tim