rspec subject{}和it{}

subject { build(:user,firstname:‘john‘,lastname:‘doe‘)}
it { should be_named ‘john doe‘}

subject { Contact.new }
sperify { should validate_presence_of :firstname } 

Rspec::Matchers.define :be_named do |expected|
    match do |actual|
        actual.name eq expected
    end
    description do 
        "return a full name as a string"
    end
end

#use the defined matchers
it { should be_named ‘John Doe‘}