Check primality of DB columns. Fixes #35.

lib/shoulda/matchers/active_record/have_db_column_matcher.rb

@@ -35,6 +35,7 @@ def with_options(opts = {})
           @default   = opts[:default]
           @null      = opts[:null]
           @scale     = opts[:scale]
+          @primary   = opts[:primary]
           self
         end
 
@@ -46,7 +47,8 @@ def matches?(subject)
             correct_limit? &&
             correct_default? &&
             correct_null? &&
-            correct_scale?
+            correct_scale? &&
+            correct_primary?
         end
 
         def failure_message
@@ -150,6 +152,21 @@ def correct_scale?
           end
         end
 
+        def correct_primary?
+          return true if @primary.nil?
+          if matched_column.primary == @primary
+            true
+          else
+            @missing = "#{model_class} has a db column named #{@column} "
+            if @primary
+              @missing << "that is not primary, but should be"
+            else
+              @missing << "that is primary, but should not be"
+            end
+            false
+          end
+        end
+
         def matched_column
           model_class.columns.detect { |each| each.name == @column.to_s }
         end

spec/shoulda/active_record/have_db_column_matcher_spec.rb

@@ -164,4 +164,22 @@
       Superhero.new.should_not @matcher
     end
   end
+
+  context "have_db_column with primary option" do
+    it "should accept a column that is primary" do
+      create_table 'superheros' do |table|
+        table.integer :id, :primary => true
+      end
+      define_model_class 'Superhero'
+      Superhero.new.should have_db_column(:id).with_options(:primary => true)
+    end
+
+    it "should reject a column that is not primary" do
+      create_table 'superheros' do |table|
+        table.integer :primary
+      end
+      define_model_class 'Superhero'
+      Superhero.new.should_not have_db_column(:primary).with_options(:primary => true)
+    end
+  end
 end