Problem
You would like to test the carrierwave imageuploader with a cucumber test, but you would also like to use a generic step that can be used with different classes and different image file column names.
Solution
Use the following and perhaps put it a file named features/common_steps.rb
Then /^the url for the column "([^"]*)" of model "([^"]*)" should be "([^"]*)"$/ do |col,mdl,url|
# First get tne class name from the mdl argument by using the Kernel.const_get method
m = Kernel.const_get(mdl).first
# And then use the send with the column name (col) to call the model's field,
# the url method of ImageUploader to get the full path
# and basename to get only the file name
File.basename(m.send(col).url).should == url
end