Rails - Sep 2007 - Removing an AR class definition, for testing plugins

I''m writing an acts_as_* plugin and am trying to BDD it.  Ideally my
specs would look like:

describe ActsAsCloneable, " basic cloning" do
  load_example_classes
  School.class_eval do
    acts_as_cloneable
  end

  before(:each) do
    @old_school = School.create! :name => "Baylake Pines", :city
=>
"Virginia Beach", :guid => "abc123"
    @clone = @old_school.build_clone
  end

  it "should preserve the attributes" do
    @clone.name.should == "Baylake Pines"
    @clone.city.should == "Virginia Beach"
    @clone.guid.should == "abc123"
  end

  it "should not clone the id" do
    @clone.id.should be_blank
  end
end

describe ActsAsCloneable, " while specifying an attribute not to
clone" do
  load_example_classes
  School.class_eval do
    acts_as_cloneable :except => :guid
  end

  before(:each) do
    @old_school = School.create! :name => "Baylake Pines", :city
=>
"Virginia Beach", :guid => "abc123"
    @clone = @old_school.build_clone
  end

  it "should preserve the regular attributes" do
    @clone.name.should == "Baylake Pines"
    @clone.city.should == "Virginia Beach"
  end

  it "should not clone the specified attribute" do
    @clone.guid.should be_blank
  end

  it "should not clone the uncloned attribute" do
    @clone.guid.should be_blank
  end
end

load_example_classes is a helper method that just defines the AR::base
classes.  The undefs would go there too.

Unfortunately what''s happening is that the definition from the second
spec is being used for the first spec...so when running both specs,
the first fails.  However if I comment out the second spec, the first
one passes.

I''ve tried using remove_const and Object.remove_class.  Neither seems
to work.  I need to start with a fresh class definition before each
description is run...how can I do that?

Pat

You can do something like in rspec/spec/spec/mocks/stub_spec.rb where  
the class is defined in before(:each).  This way your specs aren''t  
dependent on an external class definition.

Carl

On Sep 10, 2007, at 3:12 PM, Pat Maddox wrote:
> I''m writing an acts_as_* plugin and am trying to BDD it.  Ideally
my
> specs would look like:
>
> describe ActsAsCloneable, " basic cloning" do
>   load_example_classes
>   School.class_eval do
>     acts_as_cloneable
>   end
>
>   before(:each) do
>     @old_school = School.create! :name => "Baylake Pines",
:city =>
> "Virginia Beach", :guid => "abc123"
>     @clone = @old_school.build_clone
>   end
>
>   it "should preserve the attributes" do
>     @clone.name.should == "Baylake Pines"
>     @clone.city.should == "Virginia Beach"
>     @clone.guid.should == "abc123"
>   end
>
>   it "should not clone the id" do
>     @clone.id.should be_blank
>   end
> end
>
> describe ActsAsCloneable, " while specifying an attribute not to  
> clone" do
>   load_example_classes
>   School.class_eval do
>     acts_as_cloneable :except => :guid
>   end
>
>   before(:each) do
>     @old_school = School.create! :name => "Baylake Pines",
:city =>
> "Virginia Beach", :guid => "abc123"
>     @clone = @old_school.build_clone
>   end
>
>   it "should preserve the regular attributes" do
>     @clone.name.should == "Baylake Pines"
>     @clone.city.should == "Virginia Beach"
>   end
>
>   it "should not clone the specified attribute" do
>     @clone.guid.should be_blank
>   end
>
>   it "should not clone the uncloned attribute" do
>     @clone.guid.should be_blank
>   end
> end
>
> load_example_classes is a helper method that just defines the AR::base
> classes.  The undefs would go there too.
>
> Unfortunately what''s happening is that the definition from the
second
> spec is being used for the first spec...so when running both specs,
> the first fails.  However if I comment out the second spec, the first
> one passes.
>
> I''ve tried using remove_const and Object.remove_class.  Neither
seems
> to work.  I need to start with a fresh class definition before each
> description is run...how can I do that?
>
> Pat
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users

The main idea behind the solution is classes are constants, knowing
that and
also that every class inherit from Module, as you guessed remove_const
method
is the key to do it.

1) If the class you want to remove belongs to main you should do:
Object.send :remove_const,
''ClassToRemove''
>     acts_as_cloneable
>   end
>
>   before(:each) do
2) If the class you want to remove is inside a class or module you
should do:
MyModule.remove_const, ''ClassToRemove'' => outside the
module/class
self.class.send :remove_const, ''ClassToRemove'' => inside
the module/
class

Assuming you create your test class with an eval inside a test case
something like this should work:

class MyTestCase
  def setup
    eval ''class B; end''
  end

  def teardown
    self.class.send :remove_const, ''B''
  end
end

a = MyTestCase.new
a.setup      ; puts "after setup      #{MyTestCase.constants.inspect}"
# output ["B"]
a.teardown ; puts "after teardown #{MyTestCase.constants.inspect}" #
output []

On Sep 10, 5:12 pm, "Pat Maddox"
<perg...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> I''m writing an acts_as_* plugin and am trying to BDD it.  Ideally
my
> specs would look like:
>
> describe ActsAsCloneable, " basic cloning" do
>   load_example_classes
>   School.class_eval do
>     acts_as_cloneable
>   end
>
>   before(:each) do
>     @old_school = School.create! :name => "Baylake Pines",
:city =>
> "Virginia Beach", :guid => "abc123"
>     @clone = @old_school.build_clone
>   end
>
>   it "should preserve the attributes" do
>     @clone.name.should == "Baylake Pines"
>     @clone.city.should == "Virginia Beach"
>     @clone.guid.should == "abc123"
>   end
>
>   it "should not clone the id" do
>     @clone.id.should be_blank
>   end
> end
>
> describe ActsAsCloneable, " while specifying an attribute not to
clone" do
>   load_example_classes
>   School.class_eval do
>     acts_as_cloneable :except => :guid
>   end
>
>   before(:each) do
>     @old_school = School.create! :name => "Baylake Pines",
:city =>
> "Virginia Beach", :guid => "abc123"
>     @clone = @old_school.build_clone
>   end
>
>   it "should preserve the regular attributes" do
>     @clone.name.should == "Baylake Pines"
>     @clone.city.should == "Virginia Beach"
>   end
>
>   it "should not clone the specified attribute" do
>     @clone.guid.should be_blank
>   end
>
>   it "should not clone the uncloned attribute" do
>     @clone.guid.should be_blank
>   end
> end
>
> load_example_classes is a helper method that just defines the AR::base
> classes.  The undefs would go there too.
>
> Unfortunately what''s happening is that the definition from the
second
> spec is being used for the first spec...so when running both specs,
> the first fails.  However if I comment out the second spec, the first
> one passes.
>
> I''ve tried using remove_const and Object.remove_class.  Neither
seems
> to work.  I need to start with a fresh class definition before each
> description is run...how can I do that?
>
> Pat

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