Adding view matchers from Merb

lib/webrat/core.rb

@@ -8,3 +8,4 @@ require "webrat/core/label"
 require "webrat/core/select_option"
 require "webrat/core/session"
 require "webrat/core/methods"
+require "webrat/core/matchers"

lib/webrat/core/matchers.rb

@@ -0,0 +1,234 @@
+module Webrat
+  module Matchers
+  
+    class HaveXpath
+      def initialize(expected, &block)
+        # Require nokogiri and fall back on rexml
+        begin
+          require "nokogiri"
+        rescue LoadError => e
+          if require "rexml/document"
+            require "merb-core/vendor/nokogiri/css"
+            warn("Standard REXML library is slow. Please consider installing nokogiri.\nUse \"sudo gem install nokogiri\"")
+          end
+        end
+      
+        @expected = expected
+        @block    = block
+      end
+    
+      def matches?(stringlike)
+        if defined?(Nokogiri::XML)
+          matches_nokogiri?(stringlike)
+        else
+          matches_rexml?(stringlike)
+        end
+      end
+    
+      def matches_rexml?(stringlike)
+        stringlike = stringlike.body.to_s if stringlike.respond_to?(:body)
+      
+        @document = case stringlike
+        when REXML::Document
+          stringlike.root
+        when REXML::Node
+          stringlike
+        when StringIO, String
+          begin
+            REXML::Document.new(stringlike.to_s).root
+          rescue REXML::ParseException => e
+            if e.message.include?("second root element")
+              REXML::Document.new("<fake-root-element>#{stringlike}</fake-root-element>").root
+            else
+              raise e
+            end
+          end
+        end
+      
+        query.all? do |q|
+          matched = REXML::XPath.match(@document, q)
+          matched.any? && (!block_given? || matched.all?(&@block))
+        end
+      end
+    
+      def matches_nokogiri?(stringlike)
+        stringlike = stringlike.body.to_s if stringlike.respond_to?(:body)
+      
+        @document = case stringlike
+        when Nokogiri::HTML::Document, Nokogiri::XML::NodeSet
+          stringlike
+        when StringIO
+          Nokogiri::HTML(stringlike.string)
+        else
+          Nokogiri::HTML(stringlike.to_s)
+        end
+        @document.xpath(*query).any?
+      end
+    
+      def query
+        [@expected].flatten.compact
+      end
+    
+      # ==== Returns
+      # String:: The failure message.
+      def failure_message
+        "expected following text to match xpath #{@expected}:\n#{@document}"
+      end
+
+      # ==== Returns
+      # String:: The failure message to be displayed in negative matches.
+      def negative_failure_message
+        "expected following text to not match xpath #{@expected}:\n#{@document}"
+      end    
+    end
+  
+    class HaveSelector < HaveXpath
+
+      # ==== Returns
+      # String:: The failure message.
+      def failure_message
+        "expected following text to match selector #{@expected}:\n#{@document}"
+      end
+    
+      # ==== Returns
+      # String:: The failure message to be displayed in negative matches.
+      def negative_failure_message
+        "expected following text to not match selector #{@expected}:\n#{@document}"
+      end
+    
+      def query
+        Nokogiri::CSS::Parser.parse(*super).map { |ast| ast.to_xpath }
+      end
+  
+    end
+  
+    class HaveTag < HaveSelector
+    
+      # ==== Returns
+      # String:: The failure message.
+      def failure_message
+        "expected following output to contain a #{tag_inspect} tag:\n#{@document}"
+      end
+    
+      # ==== Returns
+      # String:: The failure message to be displayed in negative matches.
+      def negative_failure_message
+        "expected following output to omit a #{tag_inspect}:\n#{@document}"
+      end
+    
+      def tag_inspect
+        options = @expected.last.dup
+        content = options.delete(:content)
+      
+        html = "<#{@expected.first}"
+        options.each do |k,v|
+          html << " #{k}='#{v}'"
+        end
+      
+        if content
+          html << ">#{content}</#{@expected.first}>"
+        else
+          html << "/>"
+        end
+      
+        html
+      end
+    
+      def query
+        options  = @expected.last.dup
+        selector = @expected.first.to_s
+      
+        selector << ":contains('#{options.delete(:content)}')" if options[:content]
+      
+        options.each do |key, value|
+          selector << "[#{key}='#{value}']"
+        end
+      
+        Nokogiri::CSS::Parser.parse(selector).map { |ast| ast.to_xpath }
+      end
+    
+    end
+
+    class HasContent
+      def initialize(content)
+        @content = content
+      end
+
+      def matches?(element)
+        element = element.body.to_s if element.respond_to?(:body)
+        @element = element
+      
+        case @content
+        when String
+          @element.contains?(@content)
+        when Regexp
+          @element.matches?(@content)
+        end
+      end
+    
+      # ==== Returns
+      # String:: The failure message.
+      def failure_message
+        "expected the following element's content to #{content_message}:\n#{@element.inner_text}"
+      end
+
+      # ==== Returns
+      # String:: The failure message to be displayed in negative matches.
+      def negative_failure_message
+        "expected the following element's content to not #{content_message}:\n#{@element.inner_text}"
+      end
+    
+      def content_message
+        case @content
+        when String
+          "include \"#{@content}\""
+        when Regexp
+          "match #{@content.inspect}"
+        end
+      end
+    end
+
+    # Matches HTML content against a CSS 3 selector.
+    #
+    # ==== Parameters
+    # expected<String>:: The CSS selector to look for.
+    #
+    # ==== Returns
+    # HaveSelector:: A new have selector matcher.
+    # ---
+    # @api public
+    def have_selector(expected)
+      HaveSelector.new(expected)
+    end
+    alias_method :match_selector, :have_selector
+
+    # Matches HTML content against an XPath query
+    #
+    # ==== Parameters
+    # expected<String>:: The XPath query to look for.
+    #
+    # ==== Returns
+    # HaveXpath:: A new have xpath matcher.
+    # ---
+    # @api public
+    def have_xpath(expected)
+      HaveXpath.new(expected)
+    end
+    alias_method :match_xpath, :have_xpath
+  
+    def have_tag(name, attributes = {})
+      HaveTag.new([name, attributes])
+    end
+    alias_method :match_tag, :have_tag
+  
+    # Matches the contents of an HTML document with
+    # whatever string is supplied
+    #
+    # ---
+    # @api public
+    def contain(content)
+      HasContent.new(content)
+    end
+  
+  end
+end

spec/api/matchers_spec.rb

@@ -0,0 +1,108 @@
+require File.expand_path(File.dirname(__FILE__) + "/../spec_helper")
+
+describe Webrat::Matchers do
+  include Webrat::Matchers
+  
+  before(:each) do
+    @body = <<-EOF
+    <div id='main'>
+      <div class='inner'>hello, world!</div>
+    </div>
+    EOF
+  end
+  
+  describe "#have_selector" do
+    
+    it "should be able to match a CSS selector" do
+      @body.should have_selector("div")
+    end
+    
+    it "should not match a CSS selector that does not exist" do
+      @body.should_not have_selector("p")
+    end
+    
+    it "should be able to loop over all the matched elements" do
+      @body.should have_selector("div") { |node| node.name.should == "div" }
+    end
+    
+    it "should not match of any of the matchers in the block fail" do
+      lambda {
+        @body.should_not have_selector("div") { |node| node.name.should == "p" }
+      }.should raise_error(Spec::Expectations::ExpectationNotMetError)
+    end
+    
+  end
+  
+  describe "#have_tag" do
+    
+    it "should be able to match a tag" do
+      @body.should have_tag("div")
+    end
+    
+    it "should not match the tag when it should not match" do
+      @body.should_not have_tag("p")
+    end
+    
+    it "should be able to specify the content of the tag" do
+      @body.should have_tag("div", :content  => "hello, world!")
+    end
+    
+    it "should be able to specify the attributes of the tag" do
+      @body.should have_tag("div", :class => "inner")
+    end
+    
+  end
+   
+  describe Webrat::Matchers::HasContent do
+    include Webrat::Matchers
+    
+    before(:each) do
+      @element = stub(:element)
+      @element.stub!(:inner_text).and_return <<-EOF
+        <div id='main'>
+          <div class='inner'>hello, world!</div>
+        </div>
+      EOF
+      
+      @element.stub!(:contains?)
+      @element.stub!(:matches?)
+    end
+    
+    describe "#matches?" do
+      it "should call element#contains? when the argument is a string" do
+        @element.should_receive(:contains?)
+        
+        Webrat::Matchers::HasContent.new("hello, world!").matches?(@element)
+      end
+      
+      it "should call element#matches? when the argument is a regular expression" do
+        @element.should_receive(:matches?)
+        
+        Webrat::Matchers::HasContent.new(/hello, world/).matches?(@element)
+      end
+    end
+  
+    describe "#failure_message" do
+      it "should include the content string" do
+        hc = Webrat::Matchers::HasContent.new("hello, world!")
+        hc.matches?(@element)
+        
+        hc.failure_message.should include("\"hello, world!\"")
+      end
+      
+      it "should include the content regular expresson" do
+        hc = Webrat::Matchers::HasContent.new(/hello,\sworld!/)
+        hc.matches?(@element)
+        
+        hc.failure_message.should include("/hello,\\sworld!/")
+      end
+      
+      it "should include the element's inner content" do
+        hc = Webrat::Matchers::HasContent.new(/hello,\sworld!/)
+        hc.matches?(@element)
+        
+        hc.failure_message.should include(@element.inner_text)
+      end
+    end
+  end
+end