In addition to these specific assertions, you also have easy access to various collections that the regular test/unit assertions can be used against. These collections are:

  • assigns: Instance variables assigned in the action that are available for the view.
  • session: Objects being saved in the session.
  • flash: The flash objects currently in the session.
  • cookies: Cookies being sent to the user on this request.

These collections can be used just like any other hash:

  assert_not_nil assigns(:person) # makes sure that a @person instance variable was set
  assert_equal "Dave", cookies[:name] # makes sure that a cookie called :name was set as "Dave"
  assert flash.empty? # makes sure that there's nothing in the flash

For historic reasons, the assigns hash uses string-based keys. So assigns[:person] won’t work, but assigns["person"] will. To appease our yearning for symbols, though, an alternative accessor has been deviced using a method call instead of index referencing. So assigns(:person) will work just like assigns["person"], but again, assigns[:person] will not work.

On top of the collections, you have the complete url that a given action redirected to available in redirect_to_url.

For redirects within the same controller, you can even call follow_redirect and the redirect will be followed, triggering another action call which can then be asserted against.

Manipulating the request collections

The collections described above link to the response, so you can test if what the actions were expected to do happened. But sometimes you also want to manipulate these collections in the incoming request. This is really only relevant for sessions and cookies, though. For sessions, you just do:

  @request.session[:key] = "value"

For cookies, you need to manually create the cookie, like this:

  @request.cookies["key"] = CGI::Cookie.new("key", "value")

Testing named routes

If you’re using named routes, they can be easily tested using the original named routes methods straight in the test case. Example:

 assert_redirected_to page_url(:title => 'foo')
Methods
Public Instance methods
assert_dom_equal(expected, actual, message="")

test 2 html strings to be equivalent, i.e. identical up to reordering of attributes

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 286
286:       def assert_dom_equal(expected, actual, message="")
287:         clean_backtrace do
288:           expected_dom = HTML::Document.new(expected).root
289:           actual_dom = HTML::Document.new(actual).root
290:           full_message = build_message(message, "<?> expected to be == to\n<?>.", expected_dom.to_s, actual_dom.to_s)
291:           assert_block(full_message) { expected_dom == actual_dom }
292:         end
293:       end
assert_dom_not_equal(expected, actual, message="")

negated form of assert_dom_equivalent

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 296
296:       def assert_dom_not_equal(expected, actual, message="")
297:         clean_backtrace do
298:           expected_dom = HTML::Document.new(expected).root
299:           actual_dom = HTML::Document.new(actual).root
300:           full_message = build_message(message, "<?> expected to be != to\n<?>.", expected_dom.to_s, actual_dom.to_s)
301:           assert_block(full_message) { expected_dom != actual_dom }
302:         end
303:       end
assert_generates(expected_path, options, defaults={}, extras = {}, message=nil)

Asserts that the provided options can be used to generate the provided path.

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 145
145:       def assert_generates(expected_path, options, defaults={}, extras = {}, message=nil)
146:         clean_backtrace do 
147:           expected_path = "/#{expected_path}" unless expected_path[0] == ?/
148:           # Load routes.rb if it hasn't been loaded.
149:           ActionController::Routing::Routes.reload if ActionController::Routing::Routes.empty? 
150:       
151:           generated_path, extra_keys = ActionController::Routing::Routes.generate(options, extras)
152:           found_extras = options.reject {|k, v| ! extra_keys.include? k}
153: 
154:           msg = build_message(message, "found extras <?>, not <?>", found_extras, extras)
155:           assert_block(msg) { found_extras == extras }
156:       
157:           msg = build_message(message, "The generated path <?> did not match <?>", generated_path, 
158:               expected_path)
159:           assert_block(msg) { expected_path == generated_path }
160:         end
161:       end
assert_no_tag(*opts)

Identical to assert_tag, but asserts that a matching tag does not exist. (See assert_tag for a full discussion of the syntax.)

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 277
277:       def assert_no_tag(*opts)
278:         clean_backtrace do
279:           opts = opts.size > 1 ? opts.last.merge({ :tag => opts.first.to_s }) : opts.first
280:           tag = find_tag(opts)
281:           assert !tag, "expected no tag, but found tag matching #{opts.inspect} in:\n#{@response.body.inspect}"
282:         end
283:       end
assert_recognizes(expected_options, path, extras={}, message=nil)

Asserts that the routing of the given path was handled correctly and that the parsed options match.

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 123
123:       def assert_recognizes(expected_options, path, extras={}, message=nil)
124:         clean_backtrace do 
125:           path = "/#{path}" unless path[0..0] == '/'
126:           # Load routes.rb if it hasn't been loaded.
127:           ActionController::Routing::Routes.reload if ActionController::Routing::Routes.empty? 
128:       
129:           # Assume given controller
130:           request = ActionController::TestRequest.new({}, {}, nil)
131:           request.path = path
132:           ActionController::Routing::Routes.recognize!(request)
133:       
134:           expected_options = expected_options.clone
135:           extras.each_key { |key| expected_options.delete key } unless extras.nil?
136:       
137:           expected_options.stringify_keys!
138:           msg = build_message(message, "The recognized options <?> did not match <?>", 
139:               request.path_parameters, expected_options)
140:           assert_block(msg) { request.path_parameters == expected_options }
141:         end
142:       end
assert_redirected_to(options = {}, message=nil)

Assert that the redirection options passed in match those of the redirect called in the latest action. This match can be partial, such that assert_redirected_to(:controller => "weblog") will also match the redirection of redirect_to(:controller => "weblog", :action => "show") and so on.

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 73
 73:       def assert_redirected_to(options = {}, message=nil)
 74:         clean_backtrace do
 75:           assert_response(:redirect, message)
 76: 
 77:           if options.is_a?(String)
 78:             msg = build_message(message, "expected a redirect to <?>, found one to <?>", options, @response.redirect_url)
 79:             url_regexp = %r{^(\w+://.*?(/|$|\?))(.*)$}
 80:             eurl, epath, url, path = [options, @response.redirect_url].collect do |url|
 81:               u, p = (url_regexp =~ url) ? [$1, $3] : [nil, url]
 82:               [u, (p[0..0] == '/') ? p : '/' + p]
 83:             end.flatten
 84: 
 85:             assert_equal(eurl, url, msg) if eurl && url
 86:             assert_equal(epath, path, msg) if epath && path 
 87:           else
 88:             @response_diff = options.diff(@response.redirected_to) if options.is_a?(Hash) && @response.redirected_to.is_a?(Hash)
 89:             msg = build_message(message, "response is not a redirection to all of the options supplied (redirection is <?>)#{', difference: <?>' if @response_diff}", 
 90:                                 @response.redirected_to || @response.redirect_url, @response_diff)
 91: 
 92:             assert_block(msg) do
 93:               if options.is_a?(Symbol)
 94:                 @response.redirected_to == options
 95:               else
 96:                 options.keys.all? do |k|
 97:                   if k == :controller then options[k] == ActionController::Routing.controller_relative_to(@response.redirected_to[k], @controller.class.controller_path)
 98:                   else options[k] == (@response.redirected_to[k].respond_to?(:to_param) ? @response.redirected_to[k].to_param : @response.redirected_to[k] unless @response.redirected_to[k].nil?)
 99:                   end
100:                 end
101:               end
102:             end
103:           end
104:         end
105:       end
assert_response(type, message = nil)

Asserts that the response is one of the following types:

  • :success: Status code was 200
  • :redirect: Status code was in the 300-399 range
  • :missing: Status code was 404
  • :error: Status code was in the 500-599 range

You can also pass an explicit status code number as the type, like assert_response(501)

    # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 58
58:       def assert_response(type, message = nil)
59:         clean_backtrace do
60:           if [ :success, :missing, :redirect, :error ].include?(type) && @response.send("#{type}?")
61:             assert_block("") { true } # to count the assertion
62:           elsif type.is_a?(Fixnum) && @response.response_code == type
63:             assert_block("") { true } # to count the assertion
64:           else
65:             assert_block(build_message(message, "Expected response to be a <?>, but was <?>", type, @response.response_code)) { false }
66:           end               
67:         end
68:       end
assert_routing(path, options, defaults={}, extras={}, message=nil)

Asserts that path and options match both ways; in other words, the URL generated from options is the same as path, and also that the options recognized from path are the same as options

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 165
165:       def assert_routing(path, options, defaults={}, extras={}, message=nil)
166:         assert_recognizes(options, path, extras, message)
167:         
168:         controller, default_controller = options[:controller], defaults[:controller] 
169:         if controller && controller.include?(?/) && default_controller && default_controller.include?(?/)
170:           options[:controller] = "/#{controller}"
171:         end
172:          
173:         assert_generates(path, options, defaults, extras, message)
174:       end
assert_tag(*opts)

Asserts that there is a tag/node/element in the body of the response that meets all of the given conditions. The conditions parameter must be a hash of any of the following keys (all are optional):

  • :tag: the node type must match the corresponding value
  • :attributes: a hash. The node’s attributes must match the corresponding values in the hash.
  • :parent: a hash. The node’s parent must match the corresponding hash.
  • :child: a hash. At least one of the node’s immediate children must meet the criteria described by the hash.
  • :ancestor: a hash. At least one of the node’s ancestors must meet the criteria described by the hash.
  • :descendant: a hash. At least one of the node’s descendants must meet the criteria described by the hash.
  • :sibling: a hash. At least one of the node’s siblings must meet the criteria described by the hash.
  • :after: a hash. The node must be after any sibling meeting the criteria described by the hash, and at least one sibling must match.
  • :before: a hash. The node must be before any sibling meeting the criteria described by the hash, and at least one sibling must match.
  • :children: a hash, for counting children of a node. Accepts the keys:
    • :count: either a number or a range which must equal (or include) the number of children that match.
    • :less_than: the number of matching children must be less than this number.
    • :greater_than: the number of matching children must be greater than this number.
    • :only: another hash consisting of the keys to use to match on the children, and only matching children will be counted.
  • :content: the textual content of the node must match the
      given value. This will not match HTML tags in the body of a
      tag--only text.
    

Conditions are matched using the following algorithm:

  • if the condition is a string, it must be a substring of the value.
  • if the condition is a regexp, it must match the value.
  • if the condition is a number, the value must match number.to_s.
  • if the condition is true, the value must not be nil.
  • if the condition is false or nil, the value must be nil.

Usage:

  # assert that there is a "span" tag
  assert_tag :tag => "span"

  # assert that there is a "span" tag with id="x"
  assert_tag :tag => "span", :attributes => { :id => "x" }

  # assert that there is a "span" tag using the short-hand
  assert_tag :span

  # assert that there is a "span" tag with id="x" using the short-hand
  assert_tag :span, :attributes => { :id => "x" }

  # assert that there is a "span" inside of a "div"
  assert_tag :tag => "span", :parent => { :tag => "div" }

  # assert that there is a "span" somewhere inside a table
  assert_tag :tag => "span", :ancestor => { :tag => "table" }

  # assert that there is a "span" with at least one "em" child
  assert_tag :tag => "span", :child => { :tag => "em" }

  # assert that there is a "span" containing a (possibly nested)
  # "strong" tag.
  assert_tag :tag => "span", :descendant => { :tag => "strong" }

  # assert that there is a "span" containing between 2 and 4 "em" tags
  # as immediate children
  assert_tag :tag => "span",
             :children => { :count => 2..4, :only => { :tag => "em" } }

  # get funky: assert that there is a "div", with an "ul" ancestor
  # and an "li" parent (with "class" = "enum"), and containing a
  # "span" descendant that contains text matching /hello world/
  assert_tag :tag => "div",
             :ancestor => { :tag => "ul" },
             :parent => { :tag => "li",
                          :attributes => { :class => "enum" } },
             :descendant => { :tag => "span",
                              :child => /hello world/ }

<strong>Please note</strong: assert_tag and assert_no_tag only work with well-formed XHTML. They recognize a few tags as implicitly self-closing (like br and hr and such) but will not work correctly with tags that allow optional closing tags (p, li, td). You must explicitly close all of your tags to use these assertions.

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 267
267:       def assert_tag(*opts)
268:         clean_backtrace do
269:           opts = opts.size > 1 ? opts.last.merge({ :tag => opts.first.to_s }) : opts.first
270:           tag = find_tag(opts)
271:           assert tag, "expected tag, but no tag found matching #{opts.inspect} in:\n#{@response.body.inspect}"
272:         end
273:       end
assert_template(expected = nil, message=nil)

Asserts that the request was rendered with the appropriate template file.

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 108
108:       def assert_template(expected = nil, message=nil)
109:         clean_backtrace do
110:           rendered = expected ? @response.rendered_file(!expected.include?('/')) : @response.rendered_file
111:           msg = build_message(message, "expecting <?> but rendering with <?>", expected, rendered)
112:           assert_block(msg) do
113:             if expected.nil?
114:               !@response.rendered_with_file?
115:             else
116:               expected == rendered
117:             end
118:           end               
119:         end
120:       end
assert_valid(record)

ensures that the passed record is valid by active record standards. returns the error messages if not

     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 306
306:       def assert_valid(record)
307:         clean_backtrace do
308:           assert record.valid?, record.errors.full_messages.join("\n")
309:         end
310:       end
clean_backtrace() {|| ...}
     # File vendor/rails/actionpack/lib/action_controller/assertions.rb, line 312
312:       def clean_backtrace(&block)
313:         yield
314:       rescue AssertionFailedError => e         
315:         path = File.expand_path(__FILE__)
316:         raise AssertionFailedError, e.message, e.backtrace.reject { |line| File.expand_path(line) =~ /#{path}/ }
317:       end