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

1 files changed, 35 insertions, 0 deletions

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
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