diff --git a/lib/arel/algebra/attributes/attribute.rb b/lib/arel/algebra/attributes/attribute.rb
index f4cec828e3..03cf44a552 100644
--- a/lib/arel/algebra/attributes/attribute.rb
+++ b/lib/arel/algebra/attributes/attribute.rb
@@ -160,16 +160,13 @@ module Arel
       def type_cast_to_numeric(value, method)
         return unless value
         if value.respond_to?(:to_str)
-          if value.to_str =~ /\A(-?(?:0|[1-9]\d*)(?:\.\d+)?|(?:\.\d+))\z/
-            $1.send(method)
-          else
-            value
-          end
+          str = value.to_str.strip
+          return if str.empty?
+          return $1.send(method) if str =~ /\A(-?(?:0|[1-9]\d*)(?:\.\d+)?|(?:\.\d+))\z/
         elsif value.respond_to?(method)
-          value.send(method)
-        else
-          raise typecast_error(value)
+          return value.send(method)
         end
+        raise typecast_error(value)
       end
 
       def typecast_error(value)
diff --git a/lib/arel/algebra/attributes/boolean.rb b/lib/arel/algebra/attributes/boolean.rb
index 0ca7cd6d24..d69f2465df 100644
--- a/lib/arel/algebra/attributes/boolean.rb
+++ b/lib/arel/algebra/attributes/boolean.rb
@@ -3,11 +3,12 @@ module Arel
     class Boolean < Attribute
       def type_cast(value)
         case value
-        when true, false    then value
-        when nil            then options[:allow_nil] ? nil : false
-        when 1              then true
-        when 0              then false
-        else                
+        when true, false then value
+        # when nil            then options[:allow_nil] ? nil : false
+        when nil         then false
+        when 1           then true
+        when 0           then false
+        else
           case value.to_s.downcase.strip
           when 'true'  then true
           when 'false' then false
diff --git a/spec/arel/algebra/integration/basic_spec.rb b/spec/arel/algebra/integration/basic_spec.rb
index 6ade5c40ac..7aa4f7305c 100644
--- a/spec/arel/algebra/integration/basic_spec.rb
+++ b/spec/arel/algebra/integration/basic_spec.rb
@@ -1,50 +1,5 @@
 require 'spec_helper'
 
-module Arel
-  module Testing
-    class Engine
-      attr_reader :rows
-
-      def initialize
-        @rows = []
-      end
-
-      def supports(operation)
-        false
-      end
-
-      def read(relation)
-        @rows.dup.map { |r| Row.new(relation, r) }
-      end
-
-      def create(insert)
-        @rows << insert.record.tuple
-        insert
-      end
-    end
-  end
-end
-
-class Thing < Arel::Relation
-  attr_reader :engine, :attributes
-
-  def initialize(engine, attributes)
-    @engine, @attributes = engine, []
-    attributes.each do |name, type|
-      @attributes << type.new(self, name)
-    end
-  end
-
-  def format(attribute, value)
-    value
-  end
-
-  def insert(row)
-    insert = super Arel::Row.new(self, row)
-    insert.record
-  end
-end
-
 def have_rows(expected)
   simple_matcher "have rows" do |given, matcher|
     found, got, expected = [], [], expected.map { |r| r.tuple }
@@ -101,11 +56,14 @@ module Arel
   describe "Relation" do
 
     before :all do
-      @engine   = Testing::Engine.new
-      @relation = Thing.new(@engine,
-        :id   => Attributes::Integer,
-        :name => Attributes::String,
-        :age  => Attributes::Integer)
+      @engine = Testing::Engine.new
+      @relation = Model.build do |r|
+        r.engine @engine
+
+        r.attribute :id,   Attributes::Integer
+        r.attribute :name, Attributes::String
+        r.attribute :age,  Attributes::Integer
+      end
     end
 
     describe "..." do
diff --git a/spec/attributes/boolean_spec.rb b/spec/attributes/boolean_spec.rb
new file mode 100644
index 0000000000..bb7eeb886d
--- /dev/null
+++ b/spec/attributes/boolean_spec.rb
@@ -0,0 +1,57 @@
+require 'spec_helper'
+
+module Arel
+  describe "Attributes::Boolean" do
+
+    before :all do
+      @relation = Model.build do |r|
+        r.engine Testing::Engine.new
+        r.attribute :awesome, Attributes::Boolean
+      end
+    end
+
+    def type_cast(val)
+      @relation[:awesome].type_cast(val)
+    end
+
+    describe "#type_cast" do
+      it "returns same value if passed a boolean" do
+        val = true
+        type_cast(val).should eql(val)
+      end
+
+      it "returns boolean representation (false) of nil" do
+        type_cast(nil).should eql(false)
+      end
+
+      it "returns boolean representation of 'true', 'false'" do
+        type_cast('true').should eql(true)
+        type_cast('false').should eql(false)
+      end
+
+      it "returns boolean representation of :true, :false" do
+        type_cast(:true).should eql(true)
+        type_cast(:false).should eql(false)
+      end
+
+      it "returns boolean representation of 0, 1" do
+        type_cast(1).should == true
+        type_cast(0).should == false
+      end
+
+      it "calls #to_s on arbitrary objects" do
+        obj = Object.new
+        obj.extend Module.new { def to_s ; 'true' ; end }
+        type_cast(obj).should == true
+      end
+
+      [ Object.new, 'string', '00.0', 5 ].each do |value|
+        it "raises exception when attempting type_cast of non-boolean value #{value.inspect}" do
+          lambda do
+            type_cast(value)
+          end.should raise_error(TypecastError, /could not typecast/)
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/attributes/float_spec.rb b/spec/attributes/float_spec.rb
new file mode 100644
index 0000000000..3d8acbde7b
--- /dev/null
+++ b/spec/attributes/float_spec.rb
@@ -0,0 +1,119 @@
+require 'spec_helper'
+require 'bigdecimal'
+
+module Arel
+  describe "Attributes::Float" do
+
+    before :all do
+      @relation = Model.build do |r|
+        r.engine Testing::Engine.new
+        r.attribute :percentage, Attributes::Float
+      end
+    end
+
+    def type_cast(val)
+      @relation[:percentage].type_cast(val)
+    end
+
+    describe "#type_cast" do
+      it "returns same value if an float" do
+        type_cast(24.01).should eql(24.01)
+      end
+
+      it "returns nil if passed nil" do
+        type_cast(nil).should be_nil
+      end
+
+      it "returns nil if passed empty string" do
+        type_cast('').should be_nil
+      end
+
+      it "returns float representation of a zero string float" do
+        type_cast('0').should eql(0.0)
+      end
+
+      it "returns float representation of a positive string integer" do
+        type_cast('24').should eql(24.0)
+      end
+
+      it "returns float representation of a positive string integer with spaces" do
+        type_cast('  24').should eql(24.0)
+        type_cast('24  ').should eql(24.0)
+      end
+
+      it "returns float representation of a negative string float" do
+        type_cast('-24.23').should eql(-24.23)
+      end
+
+      it "returns float representation of a negative string integer with spaces" do
+        type_cast('-24 ').should eql(-24.0)
+        type_cast(' -24').should eql(-24.0)
+      end
+
+      it "returns integer representation of a zero string float" do
+        type_cast('0.0').should eql(0.0)
+      end
+
+      it "returns integer representation of a positive string float" do
+        type_cast('24.35').should eql(24.35)
+      end
+
+      it "returns integer representation of a positive string float with spaces" do
+        type_cast(' 24.35').should eql(24.35)
+        type_cast('24.35 ').should eql(24.35)
+      end
+
+      it "returns integer representation of a negative string float" do
+        type_cast('-24.35').should eql(-24.35)
+      end
+
+      it "returns integer representation of a negative string float with spaces" do
+        type_cast(' -24.35 ').should eql(-24.35)
+      end
+
+      it "returns integer representation of a zero string float, with no leading digits" do
+        type_cast('.0').should eql(0.0)
+      end
+
+      it "returns integer representation of a zero string float, with no leading digits with spaces" do
+        type_cast(' .0').should eql(0.0)
+      end
+
+      it "returns integer representation of a positive string float, with no leading digits" do
+        type_cast('.41').should eql(0.41)
+      end
+
+      it "returns integer representation of a zero float" do
+        type_cast(0.0).should eql(0.0)
+      end
+
+      it "returns integer representation of a positive float" do
+        type_cast(24.35).should eql(24.35)
+      end
+
+      it "returns integer representation of a negative float" do
+        type_cast(-24.35).should eql(-24.35)
+      end
+
+      it "returns integer representation of a zero decimal" do
+        type_cast(BigDecimal('0.0')).should eql(0.0)
+      end
+
+      it "returns integer representation of a positive decimal" do
+        type_cast(BigDecimal('24.35')).should eql(24.35)
+      end
+
+      it "returns integer representation of a negative decimal" do
+        type_cast(BigDecimal('-24.35')).should eql(-24.35)
+      end
+
+      [ Object.new, true, '00.0', '0.', 'string' ].each do |value|
+        it "raises exception when attempting type_cast of non-numeric value #{value.inspect}" do
+          lambda do
+            type_cast(value)
+          end.should raise_error(TypecastError, /could not typecast/)
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/attributes/integer_spec.rb b/spec/attributes/integer_spec.rb
new file mode 100644
index 0000000000..611bbf2b24
--- /dev/null
+++ b/spec/attributes/integer_spec.rb
@@ -0,0 +1,119 @@
+require 'spec_helper'
+require 'bigdecimal'
+
+module Arel
+  describe "Attributes::Integer" do
+
+    before :all do
+      @relation = Model.build do |r|
+        r.engine Testing::Engine.new
+        r.attribute :age, Attributes::Integer
+      end
+    end
+
+    def type_cast(val)
+      @relation[:age].type_cast(val)
+    end
+
+    describe "#type_cast" do
+      it "returns same value if an integer" do
+        type_cast(24).should eql(24)
+      end
+
+      it "returns nil if passed nil" do
+        type_cast(nil).should be_nil
+      end
+
+      it "returns nil if passed empty string" do
+        type_cast('').should be_nil
+      end
+
+      it "returns integer representation of a zero string integer" do
+        type_cast('0').should eql(0)
+      end
+
+      it "returns integer representation of a positive string integer" do
+        type_cast('24').should eql(24)
+      end
+
+      it "returns integer representation of a positive string integer with spaces" do
+        type_cast('  24').should eql(24)
+        type_cast('24  ').should eql(24)
+      end
+
+      it "returns integer representation of a negative string integer" do
+        type_cast('-24').should eql(-24)
+      end
+
+      it "returns integer representation of a negative string integer with spaces" do
+        type_cast('-24 ').should eql(-24)
+        type_cast(' -24').should eql(-24)
+      end
+
+      it "returns integer representation of a zero string float" do
+        type_cast('0.0').should eql(0)
+      end
+
+      it "returns integer representation of a positive string float" do
+        type_cast('24.35').should eql(24)
+      end
+
+      it "returns integer representation of a positive string float with spaces" do
+        type_cast(' 24.35').should eql(24)
+        type_cast('24.35 ').should eql(24)
+      end
+
+      it "returns integer representation of a negative string float" do
+        type_cast('-24.35').should eql(-24)
+      end
+
+      it "returns integer representation of a negative string float with spaces" do
+        type_cast(' -24.35 ').should eql(-24)
+      end
+
+      it "returns integer representation of a zero string float, with no leading digits" do
+        type_cast('.0').should eql(0)
+      end
+
+      it "returns integer representation of a zero string float, with no leading digits with spaces" do
+        type_cast(' .0').should eql(0)
+      end
+
+      it "returns integer representation of a positive string float, with no leading digits" do
+        type_cast('.41').should eql(0)
+      end
+
+      it "returns integer representation of a zero float" do
+        type_cast(0.0).should eql(0)
+      end
+
+      it "returns integer representation of a positive float" do
+        type_cast(24.35).should eql(24)
+      end
+
+      it "returns integer representation of a negative float" do
+        type_cast(-24.35).should eql(-24)
+      end
+
+      it "returns integer representation of a zero decimal" do
+        type_cast(BigDecimal('0.0')).should eql(0)
+      end
+
+      it "returns integer representation of a positive decimal" do
+        type_cast(BigDecimal('24.35')).should eql(24)
+      end
+
+      it "returns integer representation of a negative decimal" do
+        type_cast(BigDecimal('-24.35')).should eql(-24)
+      end
+
+      [ Object.new, true, '00.0', '0.', 'string' ].each do |value|
+        it "raises exception when attempting type_cast of non-numeric value #{value.inspect}" do
+          lambda do
+            type_cast(value)
+          end.should raise_error(TypecastError, /could not typecast/)
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/attributes/string_spec.rb b/spec/attributes/string_spec.rb
new file mode 100644
index 0000000000..f6d65dd045
--- /dev/null
+++ b/spec/attributes/string_spec.rb
@@ -0,0 +1,43 @@
+require 'spec_helper'
+require 'bigdecimal'
+
+module Arel
+  describe "Attributes::String" do
+
+    before :all do
+      @relation = Model.build do |r|
+        r.engine Testing::Engine.new
+        r.attribute :name, Attributes::String
+      end
+    end
+
+    def type_cast(val)
+      @relation[:name].type_cast(val)
+    end
+
+    describe "#type_cast" do
+      it "returns same value if passed a String" do
+        val = "hell"
+        type_cast(val).should eql(val)
+      end
+
+      it "returns nil if passed nil" do
+        type_cast(nil).should be_nil
+      end
+
+      it "returns String representation of Symbol" do
+        type_cast(:hello).should == "hello"
+      end
+
+      it "returns string representation of Integer" do
+        type_cast(1).should == '1'
+      end
+
+      it "calls #to_s on arbitrary objects" do
+        obj = Object.new
+        obj.extend Module.new { def to_s ; 'hello' ; end }
+        type_cast(obj).should == 'hello'
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/attributes/time_spec.rb b/spec/attributes/time_spec.rb
new file mode 100644
index 0000000000..fcbe4f58e5
--- /dev/null
+++ b/spec/attributes/time_spec.rb
@@ -0,0 +1,22 @@
+require 'spec_helper'
+require 'bigdecimal'
+
+module Arel
+  describe "Attributes::Time" do
+
+    before :all do
+      @relation = Model.build do |r|
+        r.engine Testing::Engine.new
+        r.attribute :created_at, Attributes::Time
+      end
+    end
+
+    def type_cast(val)
+      @relation[:created_at].type_cast(val)
+    end
+
+    describe "#type_cast" do
+      it "works"
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/support/model.rb b/spec/support/model.rb
new file mode 100644
index 0000000000..bd4376efcb
--- /dev/null
+++ b/spec/support/model.rb
@@ -0,0 +1,56 @@
+module Arel
+  module Testing
+    class Engine
+      attr_reader :rows
+
+      def initialize
+        @rows = []
+      end
+
+      def supports(operation)
+        false
+      end
+
+      def read(relation)
+        @rows.dup.map { |r| Row.new(relation, r) }
+      end
+
+      def create(insert)
+        @rows << insert.record.tuple
+        insert
+      end
+    end
+  end
+
+  class Model < Relation
+    attr_reader :engine, :attributes
+
+    def self.build
+      relation = new
+      yield relation
+      relation
+    end
+
+    def initialize
+      @attributes = []
+    end
+
+    def engine(engine = nil)
+      @engine = engine if engine
+      @engine
+    end
+
+    def attribute(name, type)
+      @attributes << type.new(self, name)
+    end
+
+    def format(attribute, value)
+      value
+    end
+
+    def insert(row)
+      insert = super Arel::Row.new(self, row)
+      insert.record
+    end
+  end
+end
\ No newline at end of file