Testing associations in Rspec

Problem
You would like to test your model associations in an RSpec model spec, to make sure that they are correctly set up.

Solution
After some Google searching and coming across this article here, ended up using the second method described there with the reflect_on_association method, as it doesn’t need the inclusion of another gem.
So for example to to test multiple has_many or belongs_to associations in your model rspec you could use something like:
context "check associations" do
# belongs_to associations
%w{bel_to1 bel_to2}.each do |bt|
it "should belong to #{bt}" do
m = Model.reflect_on_association(:"#{bt}")
m.macro.should == :belongs_to
end
end
# has_many associations
%w{has_many1 has_many2 has_many3}.each do |hm|
it "should have many #{hm}" do
m = Model.reflect_on_association(:"#{hm}")
m.macro.should == :has_many
end
end
end

The single-table inheritance mechanism failed to locate the subclass:

Problem
You have correctly setup your Single Table Inheritance tables as in:

class Parent < ActieRecord::Base ; end class Child < Parent ; end

but everytime you are trying to use that in a cucumber feature, or in rails console you get the following error:

The single-table inheritance mechanism failed to locate the subclass: 'child'. This error is raised because the column 'type' is reserved for storing the class in case of inheritance. Please rename this column if you didn't intend it to be used for storing the inheritance class or overwrite Parent.inheritance_column to use another column for that information. (ActiveRecord::SubclassNotFound)

Solution
Make sure that when use the subclass name in a feature, or you create a record in the database the initial letter is in capital!
So make sure that in this case the type column contains 'Child' and not 'child'