Create an Arel::Header class representing a relation's attributes

5 files changed, 45 insertions, 7 deletions

diff --git a/spec/algebra/unit/relations/join_spec.rb b/spec/algebra/unit/relations/join_spec.rb
index 9c1422c571..5fa3269052 100644
--- a/spec/algebra/unit/relations/join_spec.rb
+++ b/spec/algebra/unit/relations/join_spec.rb
@@ -18,8 +18,7 @@ module Arel
     describe '#attributes' do
       it 'combines the attributes of the two relations' do
         join = InnerJoin.new(@relation1, @relation2, @predicate)
-        join.attributes.should ==
-          (@relation1.attributes + @relation2.attributes).collect { |a| a.bind(join) }
+        join.attributes.should == (@relation1.attributes | @relation2.attributes).bind(join)
       end
     end
   end
diff --git a/spec/algebra/unit/relations/table_spec.rb b/spec/algebra/unit/relations/table_spec.rb
index d93446f1b9..d1c7cc46ba 100644
--- a/spec/algebra/unit/relations/table_spec.rb
+++ b/spec/algebra/unit/relations/table_spec.rb
@@ -9,7 +9,7 @@ module Arel
     describe '[]' do
       describe 'when given a', Symbol do
         it "manufactures an attribute if the symbol names an attribute within the relation" do
-          check @relation[:id].should == Attribute.new(@relation, :id)
+          check @relation[:id].should == Attributes::Integer.new(@relation, :id)
         end
       end
 
diff --git a/spec/attributes/header_spec.rb b/spec/attributes/header_spec.rb
new file mode 100644
index 0000000000..5811041734
--- /dev/null
+++ b/spec/attributes/header_spec.rb
@@ -0,0 +1,35 @@
+require 'spec_helper'
+
+module Arel
+  describe "Header" do
+    before :all do
+      @relation = Model.build do |r|
+        r.attribute :id,   Attributes::Integer
+        r.attribute :name, Attributes::String
+        r.attribute :age,  Attributes::Integer
+      end
+
+      @other = Model.build do |r|
+        r.attribute :foo, Attributes::String
+      end
+
+      @subset = Model.build do |r|
+        r.attribute :id, Attributes::Integer
+      end
+    end
+
+    it "finds attributes by name" do
+      @relation.attributes[:name].should == Attributes::String.new(@relation, :name)
+    end
+
+    describe "#union" do
+      it "keeps all attributes from disjoint headers" do
+        (@relation.attributes.union @other.attributes).to_ary.should have(4).items
+      end
+
+      it "keeps all attributes from both relations even if they seem like subsets" do
+        (@relation.attributes.union @subset.attributes).to_ary.should have(4).items
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/support/matchers/be_like.rb b/spec/support/matchers/be_like.rb
index 0608abbbb4..ca49b91274 100644
--- a/spec/support/matchers/be_like.rb
+++ b/spec/support/matchers/be_like.rb
@@ -1,12 +1,12 @@
 module Matchers
   class BeLike
     def initialize(expected)
-      @expected = expected
+      @expected = expected.gsub(/\s+/, ' ').strip
     end
 
     def matches?(actual)
-      @actual = actual
-      @expected.gsub(/\s+/, ' ').strip == @actual.gsub(/\s+/, ' ').strip
+      @actual = actual.gsub(/\s+/, ' ').strip
+      @expected == @actual
     end
 
     def failure_message
diff --git a/spec/support/model.rb b/spec/support/model.rb
index 10a14d7092..be692e53ec 100644
--- a/spec/support/model.rb
+++ b/spec/support/model.rb
@@ -25,7 +25,7 @@ module Arel
   class Model
     include Relation
 
-    attr_reader :engine, :attributes
+    attr_reader :engine
 
     def self.build
       relation = new
@@ -46,6 +46,10 @@ module Arel
       @attributes << type.new(self, name)
     end
 
+    def attributes
+      Header.new(@attributes)
+    end
+
     def format(attribute, value)
       value
     end