Adds the assert_select
method for use in Rails functional test cases, which can be used
to make assertions on the response HTML of a
controller action. You can also call assert_select
within
another assert_select
to make assertions on elements selected
by the enclosing assertion.
Use css_select
to select elements without making an
assertions, either from the response HTML or
elements selected by the enclosing assertion.
In addition to HTML responses, you can make the following assertions:
-
assert_select_encoded
- Assertions on HTML encoded inside XML, for example for dealing with feed item descriptions. -
assert_select_email
- Assertions on the HTML body of an e-mail.
Also see HTML::Selector to learn how to use selectors.
An assertion that selects elements and makes one or more equality tests.
If the first argument is an element, selects all matching elements starting from (and including) that element and all its children in depth-first order.
If no element if specified, calling assert_select
selects from
the response HTML unless
assert_select
is called from within an
assert_select
block.
When called with a block assert_select
passes an array of
selected elements to the block. Calling assert_select
from the
block, with no element specified, runs the assertion on the complete set of
elements selected by the enclosing assertion. Alternatively the array may
be iterated through so that assert_select
can be called
separately for each element.
Example
If the response contains two ordered lists, each with four list elements then:
assert_select "ol" do |elements| elements.each do |element| assert_select element, "li", 4 end end
will pass, as will:
assert_select "ol" do assert_select "li", 8 end
The selector may be a CSS selector expression (String), an expression with substitution values, or an HTML::Selector object.
Equality Tests
The equality test may be one of the following:
-
true
- Assertion is true if at least one element selected. -
false
- Assertion is true if no element selected. -
String/Regexp
- Assertion is true if the text value of at least one element matches the string or regular expression. -
Integer
- Assertion is true if exactly that number of elements are selected. -
Range
- Assertion is true if the number of selected elements fit the range.
If no equality test specified, the assertion is true if at least one element selected.
To perform more than one equality tests, use a hash with the following keys:
-
:text
- Narrow the selection to elements that have this text value (string or regexp). -
:html
- Narrow the selection to elements that have this HTML content (string or regexp). -
:count
- Assertion is true if the number of selected elements is equal to this value. -
:minimum
- Assertion is true if the number of selected elements is at least this value. -
:maximum
- Assertion is true if the number of selected elements is at most this value.
If the method is called with a block, once all equality tests are evaluated the block is called with an array of all matched elements.
Examples
# At least one form element assert_select "form" # Form element includes four input fields assert_select "form input", 4 # Page title is "Welcome" assert_select "title", "Welcome" # Page title is "Welcome" and there is only one title element assert_select "title", {:count => 1, :text => "Welcome"}, "Wrong title or more than one title element" # Page contains no forms assert_select "form", false, "This page must contain no forms" # Test the content and style assert_select "body div.header ul.menu" # Use substitution values assert_select "ol>li#?", %ritem-\d+/ # All input fields in the form have a name assert_select "form input" do assert_select "[name=?]", %r.+/ # Not empty end
# File actionpack/lib/action_dispatch/testing/assertions/selector.rb, line 188 def assert_select(*args, &block) # Start with optional element followed by mandatory selector. arg = args.shift @selected ||= nil if arg.is_a?(HTML::Node) # First argument is a node (tag or text, but also HTML root), # so we know what we're selecting from. root = arg arg = args.shift elsif arg == nil # This usually happens when passing a node/element that # happens to be nil. raise ArgumentError, "First argument is either selector or element to select, but nil found. Perhaps you called assert_select with an element that does not exist?" elsif @selected root = HTML::Node.new(nil) root.children.concat @selected else # Otherwise just operate on the response document. root = response_from_page end # First or second argument is the selector: string and we pass # all remaining arguments. Array and we pass the argument. Also # accepts selector itself. case arg when String selector = HTML::Selector.new(arg, args) when Array selector = HTML::Selector.new(*arg) when HTML::Selector selector = arg else raise ArgumentError, "Expecting a selector as the first argument" end # Next argument is used for equality tests. equals = {} case arg = args.shift when Hash equals = arg when String, Regexp equals[:text] = arg when Integer equals[:count] = arg when Range equals[:minimum] = arg.begin equals[:maximum] = arg.end when FalseClass equals[:count] = 0 when NilClass, TrueClass equals[:minimum] = 1 else raise ArgumentError, "I don't understand what you're trying to match" end # By default we're looking for at least one match. if equals[:count] equals[:minimum] = equals[:maximum] = equals[:count] else equals[:minimum] = 1 unless equals[:minimum] end # Last argument is the message we use if the assertion fails. message = args.shift #- message = "No match made with selector #{selector.inspect}" unless message if args.shift raise ArgumentError, "Not expecting that last argument, you either have too many arguments, or they're the wrong type" end matches = selector.select(root) # If text/html, narrow down to those elements that match it. content_mismatch = nil if match_with = equals[:text] matches.delete_if do |match| text = "" stack = match.children.reverse while node = stack.pop if node.tag? stack.concat node.children.reverse else content = node.content text << content end end text.strip! unless NO_STRIP.include?(match.name) text.sub!(%r\A\n/, '') if match.name == "textarea" unless match_with.is_a?(Regexp) ? (text =~ match_with) : (text == match_with.to_s) content_mismatch ||= build_message(message, "<?> expected but was\n<?>.", match_with, text) true end end elsif match_with = equals[:html] matches.delete_if do |match| html = match.children.map(&:to_s).join html.strip! unless NO_STRIP.include?(match.name) unless match_with.is_a?(Regexp) ? (html =~ match_with) : (html == match_with.to_s) content_mismatch ||= build_message(message, "<?> expected but was\n<?>.", match_with, html) true end end end # Expecting foo found bar element only if found zero, not if # found one but expecting two. message ||= content_mismatch if matches.empty? # Test minimum/maximum occurrence. min, max, count = equals[:minimum], equals[:maximum], equals[:count] message = message || %Q(Expected #{count_description(min, max, count)} matching "#{selector.to_s}", found #{matches.size}.) if count assert matches.size == count, message else assert matches.size >= min, message if min assert matches.size <= max, message if max end # If a block is given call that block. Set @selected to allow # nested assert_select, which can be nested several levels deep. if block_given? && !matches.empty? begin in_scope, @selected = @selected, matches yield matches ensure @selected = in_scope end end # Returns all matches elements. matches end
Extracts the body of an email and runs nested assertions on it.
You must enable deliveries for this assertion to work, use:
ActionMailer::Base.perform_deliveries = true
Examples
assert_select_email do assert_select "h1", "Email alert" end assert_select_email do items = assert_select "ol>li" items.each do # Work with items here... end end
# File actionpack/lib/action_dispatch/testing/assertions/selector.rb, line 414 def assert_select_email(&block) deliveries = ActionMailer::Base.deliveries assert !deliveries.empty?, "No e-mail in delivery list" for delivery in deliveries for part in (delivery.parts.empty? ? [delivery] : delivery.parts) if part["Content-Type"].to_s =~ %r^text\/html\W/ root = HTML::Document.new(part.body.to_s).root assert_select root, ":root", &block end end end end
Extracts the content of an element, treats it as encoded HTML and runs nested assertion on it.
You typically call this method within another assertion to operate on all currently selected elements. You can also pass an element or array of elements.
The content of each element is un-encoded, and wrapped in the root element
encoded
. It then calls the block with all un-encoded elements.
Examples
# Selects all bold tags from within the title of an ATOM feed's entries (perhaps to nab a section name prefix) assert_select_feed :atom, 1.0 do # Select each entry item and then the title item assert_select "entry>title" do # Run assertions on the encoded title elements assert_select_encoded do assert_select "b" end end end # Selects all paragraph tags from within the description of an RSS feed assert_select_feed :rss, 2.0 do # Select description element of each feed item. assert_select "channel>item>description" do # Run assertions on the encoded elements. assert_select_encoded do assert_select "p" end end end
# File actionpack/lib/action_dispatch/testing/assertions/selector.rb, line 363 def assert_select_encoded(element = nil, &block) case element when Array elements = element when HTML::Node elements = [element] when nil unless elements = @selected raise ArgumentError, "First argument is optional, but must be called from a nested assert_select" end else raise ArgumentError, "Argument is optional, and may be node or array of nodes" end fix_content = lambda do |node| # Gets around a bug in the Rails 1.1 HTML parser. node.content.gsub(%r<!\[CDATA\[(.*)(\]\]>)?/) { Rack::Utils.escapeHTML($1) } end selected = elements.map do |_element| text = _element.children.select{ |c| not c.tag? }.map{ |c| fix_content[c] }.join root = HTML::Document.new(CGI.unescapeHTML("<encoded>#{text}</encoded>")).root css_select(root, "encoded:root", &block)[0] end begin old_selected, @selected = @selected, selected assert_select ":root", &block ensure @selected = old_selected end end
Select and return all matching elements.
If called with a single argument, uses that argument as a selector to match all elements of the current page. Returns an empty array if no match is found.
If called with two arguments, uses the first argument as the base element and the second argument as the selector. Attempts to match the base element and any of its children. Returns an empty array if no match is found.
The selector may be a CSS selector expression (String), an expression with substitution values (Array) or an HTML::Selector object.
Examples
# Selects all div tags divs = css_select("div") # Selects all paragraph tags and does something interesting pars = css_select("p") pars.each do |par| # Do something fun with paragraphs here... end # Selects all list items in unordered lists items = css_select("ul>li") # Selects all form tags and then all inputs inside the form forms = css_select("form") forms.each do |form| inputs = css_select(form, "input") ... end
# File actionpack/lib/action_dispatch/testing/assertions/selector.rb, line 62 def css_select(*args) # See assert_select to understand what's going on here. arg = args.shift if arg.is_a?(HTML::Node) root = arg arg = args.shift elsif arg == nil raise ArgumentError, "First argument is either selector or element to select, but nil found. Perhaps you called assert_select with an element that does not exist?" elsif defined?(@selected) && @selected matches = [] @selected.each do |selected| subset = css_select(selected, HTML::Selector.new(arg.dup, args.dup)) subset.each do |match| matches << match unless matches.any? { |m| m.equal?(match) } end end return matches else root = response_from_page end case arg when String selector = HTML::Selector.new(arg, args) when Array selector = HTML::Selector.new(*arg) when HTML::Selector selector = arg else raise ArgumentError, "Expecting a selector as the first argument" end selector.select(root) end