Heavy metal SOAP client

Savon v2 

Testing integration with a SOAP service does not differ from testing integration with any other service. There is really no "right way" of doing this, but from my experience, it's good to have both unit and integration tests to strike a balance between test speed and reliability.

Where Savon 1.0 had Savon::Spec to mock SOAP requests, Savon 2.0 adds support for mocking requests on top of observers. Since it's always a good idea to wrap external libraries, let's assume you created a simple class for talking to some kind of authentication service.

require "savon"

class AuthenticationService

  def initialize
    @client = Savon.client(wsdl: "")

  def authenticate(message) message)


When you're using RSpec, you can include the Savon::SpecHelper module in your specs. The helper module comes with a simple mock interface available through the savon method. Instructions for MiniTest will be added asap.

require "spec_helper"

# require the helper module
require "savon/mock/spec_helper"

describe AuthenticationService do
  # include the helper module
  include Savon::SpecHelper

  # set Savon in and out of mock mode
  before(:all) { savon.mock!   }
  after(:all)  { savon.unmock! }

  describe "#authenticate" do
    it "authenticates the user with the service" do
      message = { username: "luke", password: "secret" }
      fixture ="spec/fixtures/authentication_service/authenticate.xml")

      # set up an expectation
      savon.expects(:authenticate).with(message: message).returns(fixture)

      # call the service
      service =
      response = service.authenticate(message)

      expect(response).to be_successful

As you can see in this example, you have to explicitly set Savon in and out of mock mode before and after your specs. The example uses RSpec's before and after hooks for that.


Are specified through the #expects method on the savon mock interface. It takes the name of a SOAP operation that is expected to be called.



Can be tested through the #with method. This currently only supports checking the SOAP message, but can easily be changed to support any global and or local option along with the generated request XML. This is possible because Savon mocks the request as late as possible to ensure everything works as expected in your integration tests.

If you're trying to "stub" a request, you can pass message: :any to the #with method to accept any message. You still need to call the #returns method to return a response that Savon can work with.

message = { username: "luke", password: "secret" }
savon.expects(:authenticate).with(message: message)


Should match a recorded SOAP response from the server for the request you're testing. The #returns method accepts a few options which are used to create an HTTPI response.

message = { username: "luke", password: "secret" }
fixture ="spec/fixtures/authentication_service/authenticate.xml")

savon.expects(:authenticate).with(message: message).returns(fixture)

When passed a String, like in the example above, the #returns method defaults to a response code of 200 with no headers and uses the String as the response body. You can also pass a Hash to specify all values yourself. This can be useful if you're testing SOAP fault responses which have a response code of 500.

soap_fault ="spec/fixtures/authentication_service/soap_fault.xml")

response = { code: 500, headers: {}, body: soap_fault }
savon.expects(:authenticate).with(message: message).returns(response)

This is a brand new feature, so please give it a try and let me know what you think.