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OK. I'm learning Ruby by going through the examples in Programming Ruby
by Dave Thomas. Somehow I'm stuck and I cannot progress further. I
have 3 files all in the same folder -- Song.rb, SongList.rb and
TestSongList.rb. Code is as follows:

## Song.rb
class Song
attr_reader :name, :artist, :duration
attr_writer :duration
@@plays=0
def initialize(name,artist,duration)
@name=name
@artist=artist
@duration=duration
@plays=0
end
end

## SongList.rb
def SongList
def initialize
@songs = Array.new
end

def append(song)
@songs.push(song)
self
end
end

## TestSongList.rb
require 'test/unit'
class TestSongList < Test::Unit::TestCase
def test_delete
list = SongList.new
s1 = Song.new('title1','artist1',1)
s2 = Song.new('title2','artist2',2)
s3 = Song.new('title3','artist3',3)
s4 = Song.new('title4','artist4',4)
list.append(s1).append(s2).append(s3).append(s4)

assert_equal(s1, list[0])
end
end

So I run the test and I get this:
[ookman@foorubyfiles]$ ruby ./TestSongList.rb
Loaded suite ./TestSongList
Started
E
Finished in 0.000414 seconds.

1) Error:
test_delete(TestSongList):
NameError: uninitialized constant TestSongList::SongList
./TestSongList.rb:4:in `test_delete'

1 tests, 0 assertions, 0 failures, 1 errors

Can anybody tell me why it's giving me the above error on this line?
list = SongList.new

I've tried to do:
require 'SongList' at the top of TestSongList.rb but I get the same
error. I've Googled this problem but I cannot find a resolution. I also
tried to run the TestSongList code one line at a time in irb and it
gives me the same error when it reaches line 4.

Ruby version is:
ruby 1.8.6 (2007-03-13 patchlevel 0) [i686-linux]

I appreciate any insight .... TIA!
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Can you verify you get *exactly* the same error when you require 'SongList'
at the top of your code?

Thanks!

Arlen

Alle Friday 29 February 2008, Mac Flores ha scritto:
> OK. I'm learning Ruby by going through the examples in Programming Ruby
> by Dave Thomas. Somehow I'm stuck and I cannot progress further. I
> have 3 files all in the same folder -- Song.rb, SongList.rb and
> TestSongList.rb. Code is as follows:
>
> ## Song.rb
> class Song
> attr_reader :name, :artist, :duration
> attr_writer :duration
> @@plays=0
> def initialize(name,artist,duration)
> @name=name
> @artist=artist
> @duration=duration
> @plays=0
> end
> end
>
> ## SongList.rb
> def SongList
> def initialize
> @songs = Array.new
> end
>
> def append(song)
> @songs.push(song)
> self
> end
> end
>
> ## TestSongList.rb
> require 'test/unit'
> class TestSongList < Test::Unit::TestCase
> def test_delete
> list = SongList.new
> s1 = Song.new('title1','artist1',1)
> s2 = Song.new('title2','artist2',2)
> s3 = Song.new('title3','artist3',3)
> s4 = Song.new('title4','artist4',4)
> list.append(s1).append(s2).append(s3).append(s4)
>
> assert_equal(s1, list[0])
> end
> end
>
> So I run the test and I get this:
> [ookman@foorubyfiles]$ ruby ./TestSongList.rb
> Loaded suite ./TestSongList
> Started
> E
> Finished in 0.000414 seconds.
>
> 1) Error:
> test_delete(TestSongList):
> NameError: uninitialized constant TestSongList::SongList
> ./TestSongList.rb:4:in `test_delete'
>
> 1 tests, 0 assertions, 0 failures, 1 errors
>
> Can anybody tell me why it's giving me the above error on this line?
> list = SongList.new
>
> I've tried to do:
> require 'SongList' at the top of TestSongList.rb but I get the same
> error. I've Googled this problem but I cannot find a resolution. I also
> tried to run the TestSongList code one line at a time in irb and it
> gives me the same error when it reaches line 4.
>
> Ruby version is:
> ruby 1.8.6 (2007-03-13 patchlevel 0) [i686-linux]
>
> I appreciate any insight .... TIA!

There are two problems: you need to add

require 'SongList'

in TestSongList.rb. The second is you try to create the class SongList (in
SongList.rb) using

def SongList

this creates a method called SongList, not a class. To create a class, you
need

class SongList

(as you correctly used to create class Song).

I hope this helps

Stefano

Arlen,

Thanks for your response. I get the same error when I do the require:

require 'test/unit'
require 'SongList'
class TestSongList < Test::Unit::TestCase
def test_delete
list = SongList.new
s1 = Song.new('title1','artist1',1)
s2 = Song.new('title2','artist2',2)
s3 = Song.new('title3','artist3',3)
s4 = Song.new('title4','artist4',4)
list.append(s1).append(s2).append(s3).append(s4)

assert_equal(s1, list[0])
end
end

[ookman@foo rubyfiles]$ ruby ./TestSongList.rb
Loaded suite ./TestSongList
Started
E
Finished in 0.000413 seconds.

1) Error:
test_delete(TestSongList):
NameError: uninitialized constant TestSongList::SongList
./TestSongList.rb:7:in `test_delete'

1 tests, 0 assertions, 0 failures, 1 errors



Arlen Cuss wrote:
> Can you verify you get *exactly* the same error when you require
> 'SongList'
> at the top of your code?
>
> Thanks!
>
> Arlen

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Hi,

On Sat, Mar 1, 2008 at 12:56 AM, Mac Flores <> wrote:

> Arlen,
>
> Thanks for your response. I get the same error when I do the require:
>

Ah, see Stefano's answer. Use `class', not `def'. An accidental typo.

But, I also think you'll find you need to require Song as well, otherwise
that won't exist either!

Arlen

Aarrgh! It's a typo!

Thanks, Arlen and Stefano! I've been looking at that code for so many
hours that I missed the 'class' declaration for SongList and was using
'def' instead like you observed. I changed that among other things. I
also added require 'Song' in the SongList class and require 'SongList'
in the TestSongList test class. The test runs now passes.

I appreciate your help and the extra set of eyes.

Arlen Cuss wrote:
> Hi,
>
> On Sat, Mar 1, 2008 at 12:56 AM, Mac Flores <>
> wrote:
>
>> Arlen,
>>
>> Thanks for your response. I get the same error when I do the require:
>>
>
> Ah, see Stefano's answer. Use `class', not `def'. An accidental typo.
>
> But, I also think you'll find you need to require Song as well,
> otherwise
> that won't exist either!
>
> Arlen

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