rspec_extensions.markdown

layout	title
page	Rspec Extensions

While describe and context syntactically are not very different, save for the restriction that context cannot be used as a top level element within a spec file, it is often good to use context in situations where a group of tests are exercising particular paths through the method or illustrating a particular state.

class Client

  # Connects to the specified server 
  def connect(server=@default_server)
    # ... performs connection to the server ...
  end
end

In the above situation our Client class has a #connect method which allows for a single input.

The method accepts a server as a parameter or it defaults a sever value stored within the Client instance. Here, we have identified a context when the code is executed without a server specified and with a server specified.

As this is likely a client making a connection to a server it is possible that the server is not available. Again, we have identified a context when the code may generate a different result within the code.

An example outline of the resulting test file could look like the following:

describe Client do
  describe '#connect' do
    context 'when the server value is not specified' do
      it 'should connect to the default server' do ; end
    end
    
    context 'when the server is not available' do
      it 'should raise an exception' do ; end
    end
  end
end

Each defined context here uses RSpec's context keyword with each description string starting with when. Again, this is a good practice as it makes it clear when what this context is attempting to describe.