Make assert_select's failure messages clearer about what failed. #7779 [dchelimsky]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6860 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 54 insertions, 21 deletions

diff --git a/actionpack/CHANGELOG b/actionpack/CHANGELOG
index 19771aa462..9f36aebb49 100644
--- a/actionpack/CHANGELOG
+++ b/actionpack/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Make assert_select's failure messages clearer about what failed. #7779 [dchelimsky]
+
 * Introduce a default respond_to block for custom types.  #8174 [Josh Peek]
 
 * auto_complete_field takes a :method option so you can GET or POST.  #8120 [zapnap]
diff --git a/actionpack/lib/action_controller/assertions/selector_assertions.rb b/actionpack/lib/action_controller/assertions/selector_assertions.rb
index 8de23c1f27..048bba153f 100644
--- a/actionpack/lib/action_controller/assertions/selector_assertions.rb
+++ b/actionpack/lib/action_controller/assertions/selector_assertions.rb
@@ -196,7 +196,7 @@ module ActionController
           # Otherwise just operate on the response document.
           root = response_from_page_or_rjs
         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.
@@ -209,7 +209,7 @@ module ActionController
             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
@@ -277,14 +277,10 @@ module ActionController
         # found one but expecting two.
         message ||= content_mismatch if matches.empty?
         # Test minimum/maximum occurrence.
-        if equals[:minimum]
-          assert matches.size >= equals[:minimum], message ||
-             "Expected at least #{equals[:minimum]} elements, found #{matches.size}."
-        end
-        if equals[:maximum]
-          assert matches.size <= equals[:maximum], message ||
-            "Expected at most #{equals[:maximum]} elements, found #{matches.size}."
-        end
+        min, max = equals[:minimum], equals[:maximum]
+        message = message || %(Expected #{count_description(min, max)} matching "#{selector.to_s}", found #{matches.size}.)
+        assert matches.size >= min, message if min
+        assert matches.size <= max, message if max
 
         # If a block is given call that block. Set @selected to allow
         # nested assert_select, which can be nested several levels deep.
@@ -300,7 +296,19 @@ module ActionController
         # Returns all matches elements.
         matches
       end
-
+      
+      def count_description(min, max) #:nodoc:
+        pluralize = lambda {|word, quantity| word << (quantity == 1 ? '' : 's')}
+        
+        if min && max && (max != min)
+          "between #{min} and #{max} elements"
+        elsif min && !(min == 1 && max == 1)
+          "at least #{min} #{pluralize['element', min]}"
+        elsif max
+          "at most #{max} #{pluralize['element', max]}"
+        end
+      end
+      
       # :call-seq:
       #   assert_select_rjs(id?) { |elements| ... }
       #   assert_select_rjs(statement, id?) { |elements| ... }
diff --git a/actionpack/test/controller/assert_select_test.rb b/actionpack/test/controller/assert_select_test.rb
index f3b525ab92..36075a0871 100644
--- a/actionpack/test/controller/assert_select_test.rb
+++ b/actionpack/test/controller/assert_select_test.rb
@@ -73,7 +73,12 @@ class AssertSelectTest < Test::Unit::TestCase
   def teardown
     ActionMailer::Base.deliveries.clear
   end
-
+  
+  def assert_failure(message, &block)
+    e = assert_raises(AssertionFailedError, &block)
+    assert_match(message, e.message) if Regexp === message
+    assert_equal(message, e.message) if String === message
+  end
 
   #
   # Test assert select.
@@ -82,8 +87,8 @@ class AssertSelectTest < Test::Unit::TestCase
   def test_assert_select
     render_html %Q{<div id="1"></div><div id="2"></div>}
     assert_select "div", 2
-    assert_raises(AssertionFailedError) { assert_select "div", 3 }
-    assert_raises(AssertionFailedError){ assert_select "p" }
+    assert_failure(/Expected at least 3 elements matching \"div\", found 2/) { assert_select "div", 3 }
+    assert_failure(/Expected at least 1 element matching \"p\", found 0/) { assert_select "p" }
   end
 
 
@@ -131,22 +136,34 @@ class AssertSelectTest < Test::Unit::TestCase
   end
 
 
-  def test_equality_of_instances
+  def test_counts
     render_html %Q{<div id="1">foo</div><div id="2">foo</div>}
     assert_nothing_raised               { assert_select "div", 2 }
-    assert_raises(AssertionFailedError) { assert_select "div", 3 }
+    assert_failure(/Expected at least 3 elements matching \"div\", found 2/) do
+      assert_select "div", 3
+    end
     assert_nothing_raised               { assert_select "div", 1..2 }
-    assert_raises(AssertionFailedError) { assert_select "div", 3..4 }
+    assert_failure(/Expected between 3 and 4 elements matching \"div\", found 2/) do
+      assert_select "div", 3..4
+    end
     assert_nothing_raised               { assert_select "div", :count=>2 }
-    assert_raises(AssertionFailedError) { assert_select "div", :count=>3 }
+    assert_failure(/Expected at least 3 elements matching \"div\", found 2/) do
+      assert_select "div", :count=>3
+    end
     assert_nothing_raised               { assert_select "div", :minimum=>1 }
     assert_nothing_raised               { assert_select "div", :minimum=>2 }
-    assert_raises(AssertionFailedError) { assert_select "div", :minimum=>3 }
+    assert_failure(/Expected at least 3 elements matching \"div\", found 2/) do
+      assert_select "div", :minimum=>3
+    end
     assert_nothing_raised               { assert_select "div", :maximum=>2 }
     assert_nothing_raised               { assert_select "div", :maximum=>3 }
-    assert_raises(AssertionFailedError) { assert_select "div", :maximum=>1 }
+    assert_failure(/Expected at most 1 element matching \"div\", found 2/) do
+      assert_select "div", :maximum=>1
+    end
     assert_nothing_raised               { assert_select "div", :minimum=>1, :maximum=>2 }
-    assert_raises(AssertionFailedError) { assert_select "div", :minimum=>3, :maximum=>4 }
+    assert_failure(/Expected between 3 and 4 elements matching \"div\", found 2/) do
+      assert_select "div", :minimum=>3, :maximum=>4
+    end
   end
 
 
@@ -183,6 +200,12 @@ class AssertSelectTest < Test::Unit::TestCase
         assert_select "#3", false
       end
     end
+    
+    assert_failure(/Expected at least 1 element matching \"#4\", found 0\./) do
+      assert_select "div" do
+        assert_select "#4"
+      end
+    end
   end