reorganizing tests

44 files changed, 790 insertions, 24 deletions

diff --git a/spec/arel/algebra/unit/predicates/binary_spec.rb b/spec/arel/algebra/unit/predicates/binary_spec.rb
new file mode 100644
index 0000000000..9022a543d1
--- /dev/null
+++ b/spec/arel/algebra/unit/predicates/binary_spec.rb
@@ -0,0 +1,33 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Binary do
+    before do
+      @relation = Table.new(:users)
+      @attribute1 = @relation[:id]
+      @attribute2 = @relation[:name]
+      class ConcreteBinary < Binary
+      end
+    end
+  
+    describe '#bind' do
+      before do
+        @another_relation = @relation.alias
+      end
+      
+      describe 'when both operands are attributes' do
+        it "manufactures an expression with the attributes bound to the relation" do
+          ConcreteBinary.new(@attribute1, @attribute2).bind(@another_relation). \
+            should == ConcreteBinary.new(@another_relation[@attribute1], @another_relation[@attribute2])
+        end
+      end
+      
+      describe 'when an operand is a value' do
+        it "manufactures an expression with unmodified values" do
+          ConcreteBinary.new(@attribute1, "asdf").bind(@another_relation). \
+            should == ConcreteBinary.new(@attribute1.find_correlate_in(@another_relation), "asdf".find_correlate_in(@another_relation))
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/predicates/equality_spec.rb b/spec/arel/algebra/unit/predicates/equality_spec.rb
new file mode 100644
index 0000000000..9a56ed5eaf
--- /dev/null
+++ b/spec/arel/algebra/unit/predicates/equality_spec.rb
@@ -0,0 +1,27 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Equality do
+    before do
+      @relation1 = Table.new(:users)
+      @relation2 = Table.new(:photos)
+      @attribute1 = @relation1[:id]
+      @attribute2 = @relation2[:user_id]
+    end
+  
+    describe '==' do 
+      it "obtains if attribute1 and attribute2 are identical" do
+        Equality.new(@attribute1, @attribute2).should == Equality.new(@attribute1, @attribute2)
+        Equality.new(@attribute1, @attribute2).should_not == Equality.new(@attribute1, @attribute1)
+      end
+    
+      it "obtains if the concrete type of the predicates are identical" do
+        Equality.new(@attribute1, @attribute2).should_not == Binary.new(@attribute1, @attribute2)
+      end
+    
+      it "is commutative on the attributes" do
+        Equality.new(@attribute1, @attribute2).should == Equality.new(@attribute2, @attribute1)
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/predicates/in_spec.rb b/spec/arel/algebra/unit/predicates/in_spec.rb
new file mode 100644
index 0000000000..91c154763c
--- /dev/null
+++ b/spec/arel/algebra/unit/predicates/in_spec.rb
@@ -0,0 +1,10 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe In do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/primitives/attribute_spec.rb b/spec/arel/algebra/unit/primitives/attribute_spec.rb
new file mode 100644
index 0000000000..bab9fad3d5
--- /dev/null
+++ b/spec/arel/algebra/unit/primitives/attribute_spec.rb
@@ -0,0 +1,169 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Attribute do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+  
+    describe Attribute::Transformations do
+      describe '#as' do
+        it "manufactures an aliased attributed" do
+          @attribute.as(:alias).should == Attribute.new(@relation, @attribute.name, :alias => :alias, :ancestor => @attribute)
+        end
+      end
+    
+      describe '#bind' do
+        it "manufactures an attribute with the relation bound and self as an ancestor" do
+          derived_relation = @relation.where(@relation[:id].eq(1))
+          @attribute.bind(derived_relation).should == Attribute.new(derived_relation, @attribute.name, :ancestor => @attribute)
+        end
+        
+        it "returns self if the substituting to the same relation" do
+          @attribute.bind(@relation).should == @attribute
+        end
+      end
+    
+      describe '#to_attribute' do
+        it "returns self" do
+          @attribute.to_attribute.should == @attribute
+        end
+      end
+    end
+    
+    describe '#column' do
+      it "returns the corresponding column in the relation" do
+        @attribute.column.should == @relation.column_for(@attribute)
+      end
+    end
+    
+    describe '#engine' do
+      it "delegates to its relation" do
+        Attribute.new(@relation, :id).engine.should == @relation.engine
+      end
+    end
+    
+    describe Attribute::Congruence do
+      describe '/' do
+        before do
+          @aliased_relation = @relation.alias
+          @doubly_aliased_relation = @aliased_relation.alias
+        end
+        
+        describe 'when dividing two unrelated attributes' do
+          it "returns 0.0" do
+            (@relation[:id] / @relation[:name]).should == 0.0
+          end
+        end
+        
+        describe 'when dividing two matching attributes' do
+          it 'returns a the highest score for the most similar attributes' do
+            (@aliased_relation[:id] / @relation[:id]) \
+              .should == (@aliased_relation[:id] / @relation[:id])
+            (@aliased_relation[:id] / @relation[:id]) \
+              .should < (@aliased_relation[:id] / @aliased_relation[:id])
+          end
+        end
+      end
+    end
+  
+    describe Attribute::Predications do
+      before do
+        @attribute = Attribute.new(@relation, :name)
+      end
+    
+      describe '#eq' do
+        it "manufactures an equality predicate" do
+          @attribute.eq('name').should == Equality.new(@attribute, 'name')
+        end
+      end
+    
+      describe '#lt' do
+        it "manufactures a less-than predicate" do
+          @attribute.lt(10).should == LessThan.new(@attribute, 10)
+        end
+      end
+    
+      describe '#lteq' do
+        it "manufactures a less-than or equal-to predicate" do
+          @attribute.lteq(10).should == LessThanOrEqualTo.new(@attribute, 10)
+        end
+      end
+    
+      describe '#gt' do
+        it "manufactures a greater-than predicate" do
+          @attribute.gt(10).should == GreaterThan.new(@attribute, 10)
+        end
+      end
+    
+      describe '#gteq' do
+        it "manufactures a greater-than or equal-to predicate" do
+          @attribute.gteq(10).should == GreaterThanOrEqualTo.new(@attribute, 10)
+        end
+      end
+    
+      describe '#matches' do
+        it "manufactures a match predicate" do
+          @attribute.matches(/.*/).should == Match.new(@attribute, /.*/)
+        end
+      end
+      
+      describe '#in' do
+        it "manufactures an in predicate" do
+          @attribute.in(1..30).should == In.new(@attribute, (1..30))
+        end
+      end
+    end
+  
+    describe Attribute::Expressions do
+      before do
+        @attribute = Attribute.new(@relation, :name)    
+      end
+    
+      describe '#count' do
+        it "manufactures a count Expression" do
+          @attribute.count.should == Count.new(@attribute)
+        end
+      end
+    
+      describe '#sum' do
+        it "manufactures a sum Expression" do
+          @attribute.sum.should == Sum.new(@attribute)
+        end
+      end
+    
+      describe '#maximum' do
+        it "manufactures a maximum Expression" do
+          @attribute.maximum.should == Maximum.new(@attribute)
+        end
+      end
+    
+      describe '#minimum' do
+        it "manufactures a minimum Expression" do
+          @attribute.minimum.should == Minimum.new(@attribute)
+        end
+      end
+    
+      describe '#average' do
+        it "manufactures an average Expression" do
+          @attribute.average.should == Average.new(@attribute)
+        end
+      end 
+    end
+    
+    describe Attribute::Orderings do
+      describe '#asc' do
+        it 'manufactures an ascending ordering' do
+          pending
+        end
+      end
+      
+      describe '#desc' do
+        it 'manufactures a descending ordering' do
+          pending
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/primitives/expression_spec.rb b/spec/arel/algebra/unit/primitives/expression_spec.rb
new file mode 100644
index 0000000000..10bdb56302
--- /dev/null
+++ b/spec/arel/algebra/unit/primitives/expression_spec.rb
@@ -0,0 +1,39 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Expression do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+    
+    describe Expression::Transformations do
+      before do
+        @expression = Count.new(@attribute)
+      end
+      
+      describe '#bind' do
+        it "manufactures an attribute with a rebound relation and self as the ancestor" do
+          derived_relation = @relation.where(@relation[:id].eq(1))
+          @expression.bind(derived_relation).should == Count.new(@attribute.bind(derived_relation), nil, @expression)
+        end
+        
+        it "returns self if the substituting to the same relation" do
+          @expression.bind(@relation).should == @expression
+        end
+      end
+      
+      describe '#as' do
+        it "manufactures an aliased expression" do
+          @expression.as(:alias).should == Expression.new(@attribute, :alias, @expression)
+        end
+      end
+      
+      describe '#to_attribute' do
+        it "manufactures an attribute with the expression as an ancestor" do
+          @expression.to_attribute.should == Attribute.new(@expression.relation, @expression.alias, :ancestor => @expression)
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/primitives/value_spec.rb b/spec/arel/algebra/unit/primitives/value_spec.rb
new file mode 100644
index 0000000000..8774ca78c5
--- /dev/null
+++ b/spec/arel/algebra/unit/primitives/value_spec.rb
@@ -0,0 +1,15 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Value do
+    before do
+      @relation = Table.new(:users)
+    end
+
+    describe '#bind' do
+      it "manufactures a new value whose relation is the provided relation" do
+        Value.new(1, @relation).bind(another_relation = Table.new(:photos)).should == Value.new(1, another_relation)
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/alias_spec.rb b/spec/arel/algebra/unit/relations/alias_spec.rb
new file mode 100644
index 0000000000..c87a0ca2dd
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/alias_spec.rb
@@ -0,0 +1,16 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Alias do
+    before do
+      @relation = Table.new(:users)
+    end
+    
+    describe '==' do
+      it "obtains if the objects are the same" do
+        Alias.new(@relation).should_not == Alias.new(@relation)
+        (aliaz = Alias.new(@relation)).should == aliaz
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/delete_spec.rb b/spec/arel/algebra/unit/relations/delete_spec.rb
new file mode 100644
index 0000000000..075e59e724
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/delete_spec.rb
@@ -0,0 +1,9 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Deletion do
+    before do
+      @relation = Table.new(:users)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/group_spec.rb b/spec/arel/algebra/unit/relations/group_spec.rb
new file mode 100644
index 0000000000..050de2993d
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/group_spec.rb
@@ -0,0 +1,10 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Group do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/insert_spec.rb b/spec/arel/algebra/unit/relations/insert_spec.rb
new file mode 100644
index 0000000000..184cd2a926
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/insert_spec.rb
@@ -0,0 +1,9 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Insert do
+    before do
+      @relation = Table.new(:users)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/join_spec.rb b/spec/arel/algebra/unit/relations/join_spec.rb
new file mode 100644
index 0000000000..5b512cc7f6
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/join_spec.rb
@@ -0,0 +1,26 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Join do
+    before do
+      @relation1 = Table.new(:users)
+      @relation2 = Table.new(:photos)
+      @predicate = @relation1[:id].eq(@relation2[:user_id])
+    end
+    
+    describe 'hashing' do
+      it 'implements hash equality' do
+        InnerJoin.new(@relation1, @relation2, @predicate) \
+          .should hash_the_same_as(InnerJoin.new(@relation1, @relation2, @predicate))
+      end
+    end
+    
+    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) }
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/order_spec.rb b/spec/arel/algebra/unit/relations/order_spec.rb
new file mode 100644
index 0000000000..0e1b1a0e54
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/order_spec.rb
@@ -0,0 +1,11 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Order do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+  end
+end
+  
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/project_spec.rb b/spec/arel/algebra/unit/relations/project_spec.rb
new file mode 100644
index 0000000000..b71acf5e91
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/project_spec.rb
@@ -0,0 +1,34 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Project do
+    before do
+      @relation = Table.new(:users)
+      @attribute = @relation[:id]
+    end
+    
+    describe '#attributes' do
+      before do
+        @projection = Project.new(@relation, @attribute)
+      end
+      
+      it "manufactures attributes associated with the projection relation" do
+        @projection.attributes.should == [@attribute].collect { |a| a.bind(@projection) }
+      end
+    end
+    
+    describe '#externalizable?' do
+      describe 'when the projections are attributes' do
+        it 'returns false' do
+          Project.new(@relation, @attribute).should_not be_externalizable
+        end
+      end
+      
+      describe 'when the projections include an aggregation' do
+        it "obtains" do
+          Project.new(@relation, @attribute.sum).should be_externalizable
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/relation_spec.rb b/spec/arel/algebra/unit/relations/relation_spec.rb
new file mode 100644
index 0000000000..3286f373f5
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/relation_spec.rb
@@ -0,0 +1,188 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Relation do
+    before do
+      @relation = Table.new(:users)
+      @attribute1 = @relation[:id]
+      @attribute2 = @relation[:name]
+    end
+  
+    describe '[]' do
+      describe 'when given an', Attribute do
+        it "return the attribute congruent to the provided attribute" do
+          @relation[@attribute1].should == @attribute1
+        end
+      end
+      
+      describe 'when given a', Symbol, String do
+        it "returns the attribute with the same name, if it exists" do
+          @relation[:id].should == @attribute1
+          @relation['id'].should == @attribute1
+          @relation[:does_not_exist].should be_nil
+        end
+      end
+    end
+      
+    describe Relation::Operable do
+      describe 'joins' do
+        before do
+          @predicate = @relation[:id].eq(@relation[:id])
+        end
+      
+        describe '#join' do
+          describe 'when given a relation' do
+            it "manufactures an inner join operation between those two relations" do
+              @relation.join(@relation).on(@predicate). \
+                should == InnerJoin.new(@relation, @relation, @predicate)
+            end
+          end
+          
+          describe "when given a string" do
+            it "manufactures a join operation with the string passed through" do
+              @relation.join(arbitrary_string = "ASDF").should == Join.new(arbitrary_string, @relation) 
+            end
+          end
+          
+          describe "when given something blank" do
+            it "returns self" do
+              @relation.join.should == @relation
+            end
+          end
+        end
+
+        describe '#outer_join' do
+          it "manufactures a left outer join operation between those two relations" do
+            @relation.outer_join(@relation).on(@predicate). \
+              should == OuterJoin.new(@relation, @relation, @predicate)
+          end
+        end
+      end
+
+      describe '#project' do
+        it "manufactures a projection relation" do
+          @relation.project(@attribute1, @attribute2). \
+            should == Project.new(@relation, @attribute1, @attribute2)
+        end
+        
+        describe "when given blank attributes" do
+          it "returns self" do
+            @relation.project.should == @relation
+          end
+        end
+      end
+
+      describe '#alias' do
+        it "manufactures an alias relation" do
+          @relation.alias.relation.should == Alias.new(@relation).relation
+        end
+      end
+
+      describe '#where' do
+        before do
+          @predicate = Equality.new(@attribute1, @attribute2)
+        end
+
+        it "manufactures a where relation" do
+          @relation.where(@predicate).should == Where.new(@relation, @predicate)
+        end
+
+        it "accepts arbitrary strings" do
+          @relation.where("arbitrary").should == Where.new(@relation, "arbitrary")
+        end
+
+        describe 'when given a blank predicate' do
+          it 'returns self' do
+            @relation.where.should == @relation
+          end
+        end
+      end
+  
+      describe '#order' do
+        it "manufactures an order relation" do
+          @relation.order(@attribute1, @attribute2).should == Order.new(@relation, @attribute1, @attribute2)
+        end
+        
+        describe 'when given a blank ordering' do
+          it 'returns self' do
+            @relation.order.should == @relation
+          end
+        end
+      end
+      
+      describe '#take' do
+        it "manufactures a take relation" do
+          @relation.take(5).should == Take.new(@relation, 5)
+        end
+        
+        describe 'when given a blank number of items' do
+          it 'returns self' do
+            @relation.take.should == @relation
+          end
+        end
+      end
+      
+      describe '#skip' do
+        it "manufactures a skip relation" do
+          @relation.skip(4).should == Skip.new(@relation, 4)
+        end
+        
+        describe 'when given a blank number of items' do
+          it 'returns self' do
+            @relation.skip.should == @relation
+          end
+        end
+      end
+
+      describe '#group' do
+        it 'manufactures a group relation' do
+          @relation.group(@attribute1, @attribute2).should == Group.new(@relation, @attribute1, @attribute2)
+        end
+        
+        describe 'when given blank groupings' do
+          it 'returns self' do
+            @relation.group.should == @relation
+          end
+        end
+      end
+      
+      describe Relation::Operable::Writable do
+        describe '#delete' do
+          it 'manufactures a deletion relation' do
+            Session.start do
+              mock(Session.new).delete(Deletion.new(@relation))
+              @relation.delete
+            end
+          end
+        end
+
+        describe '#insert' do
+          it 'manufactures an insertion relation' do
+            Session.start do
+              record = {@relation[:name] => 'carl'}
+              mock(Session.new).create(Insert.new(@relation, record))
+              @relation.insert(record)
+            end
+          end
+        end
+
+        describe '#update' do
+          it 'manufactures an update relation' do
+            Session.start do
+              assignments = {@relation[:name] => Value.new('bob', @relation)}
+              mock(Session.new).update(Update.new(@relation, assignments))
+              @relation.update(assignments)
+            end
+          end
+        end
+      end
+    end
+      
+    describe Relation::Enumerable do
+      it "implements enumerable" do
+        @relation.collect.should == @relation.session.read(@relation)
+        @relation.first.should == @relation.session.read(@relation).first
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/skip_spec.rb b/spec/arel/algebra/unit/relations/skip_spec.rb
new file mode 100644
index 0000000000..ff57e03d1c
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/skip_spec.rb
@@ -0,0 +1,10 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Skip do
+    before do
+      @relation = Table.new(:users)
+      @skipped = 4
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/table_spec.rb b/spec/arel/algebra/unit/relations/table_spec.rb
new file mode 100644
index 0000000000..4821d92299
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/table_spec.rb
@@ -0,0 +1,39 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Table do
+    before do
+      @relation = Table.new(:users)
+    end
+  
+    describe '[]' do
+      describe 'when given a', Symbol do
+        it "manufactures an attribute if the symbol names an attribute within the relation" do
+          @relation[:id].should == Attribute.new(@relation, :id)
+          @relation[:does_not_exist].should be_nil
+        end
+      end
+
+      describe 'when given an', Attribute do
+        it "returns the attribute if the attribute is within the relation" do
+          @relation[@relation[:id]].should == @relation[:id]
+        end
+        
+        it "returns nil if the attribtue is not within the relation" do
+          another_relation = Table.new(:photos)
+          @relation[another_relation[:id]].should be_nil
+        end
+      end
+      
+      describe 'when given an', Expression do
+        before do
+          @expression = @relation[:id].count
+        end
+        
+        it "returns the Expression if the Expression is within the relation" do
+          @relation[@expression].should be_nil
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/take_spec.rb b/spec/arel/algebra/unit/relations/take_spec.rb
new file mode 100644
index 0000000000..6f8b4fd36e
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/take_spec.rb
@@ -0,0 +1,10 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Take do
+    before do
+      @relation = Table.new(:users)
+      @taken = 4
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/update_spec.rb b/spec/arel/algebra/unit/relations/update_spec.rb
new file mode 100644
index 0000000000..c27afb48b2
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/update_spec.rb
@@ -0,0 +1,9 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Update do
+    before do
+      @relation = Table.new(:users)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/relations/where_spec.rb b/spec/arel/algebra/unit/relations/where_spec.rb
new file mode 100644
index 0000000000..3f37b53138
--- /dev/null
+++ b/spec/arel/algebra/unit/relations/where_spec.rb
@@ -0,0 +1,18 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Where do
+    before do
+      @relation = Table.new(:users)
+      @predicate = @relation[:id].eq(1)
+    end
+  
+    describe '#initialize' do
+      it "manufactures nested where relations if multiple predicates are provided" do
+        another_predicate = @relation[:name].lt(2)        
+        Where.new(@relation, @predicate, another_predicate). \
+          should == Where.new(Where.new(@relation, another_predicate), @predicate)
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/algebra/unit/session/session_spec.rb b/spec/arel/algebra/unit/session/session_spec.rb
new file mode 100644
index 0000000000..e17b5d638a
--- /dev/null
+++ b/spec/arel/algebra/unit/session/session_spec.rb
@@ -0,0 +1,84 @@
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', 'spec_helper')
+
+module Arel
+  describe Session do
+    before do
+      @relation = Table.new(:users)
+      @session = Session.new
+    end
+    
+    describe '::start' do
+      describe '::instance' do
+        it "it is a singleton within the started session" do
+          Session.start do
+            Session.new.should == Session.new
+          end
+        end
+
+        it "is a singleton across nested sessions" do
+          Session.start do
+            outside = Session.new
+            Session.start do
+              Session.new.should == outside
+            end
+          end
+        end
+      
+        it "manufactures new sessions outside of the started session" do
+          Session.new.should_not == Session.new
+        end
+      end
+    end
+    
+    describe Session::CRUD do
+      before do
+        @insert = Insert.new(@relation, @relation[:name] => 'nick')
+        @update = Update.new(@relation, @relation[:name] => 'nick')
+        @delete = Deletion.new(@relation)
+        @read = @relation
+      end
+      
+      describe '#create' do
+        it "executes an insertion on the connection" do
+          mock(@insert).call
+          @session.create(@insert)
+        end
+      end
+      
+      describe '#read' do
+        it "executes an selection on the connection" do
+          mock(@read).call
+          @session.read(@read)
+        end
+        
+        it "is memoized" do
+          mock(@read).call.once
+          @session.read(@read)
+          @session.read(@read)
+        end
+      end
+      
+      describe '#update' do
+        it "executes an update on the connection" do
+          mock(@update).call
+          @session.update(@update)
+        end
+      end
+      
+      describe '#delete' do
+        it "executes a delete on the connection" do
+          mock(@delete).call
+          @session.delete(@delete)
+        end
+      end
+    end
+    
+    describe 'Transactions' do
+      describe '#begin' do
+      end
+    
+      describe '#end' do
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/arel/integration/joins/with_adjacency_spec.rb b/spec/arel/engines/sql/integration/joins/with_adjacency_spec.rb
index ffd6498749..50b0908441 100644
--- a/spec/arel/integration/joins/with_adjacency_spec.rb
+++ b/spec/arel/engines/sql/integration/joins/with_adjacency_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Join do
diff --git a/spec/arel/integration/joins/with_aggregations_spec.rb b/spec/arel/engines/sql/integration/joins/with_aggregations_spec.rb
index 4aba005d51..709ae9f8d1 100644
--- a/spec/arel/integration/joins/with_aggregations_spec.rb
+++ b/spec/arel/engines/sql/integration/joins/with_aggregations_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Join do
diff --git a/spec/arel/integration/joins/with_compounds_spec.rb b/spec/arel/engines/sql/integration/joins/with_compounds_spec.rb
index 41f04349b8..4bceef4975 100644
--- a/spec/arel/integration/joins/with_compounds_spec.rb
+++ b/spec/arel/engines/sql/integration/joins/with_compounds_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Join do
diff --git a/spec/arel/unit/predicates/binary_spec.rb b/spec/arel/engines/sql/unit/predicates/binary_spec.rb
index 2d0c67e006..03574225c2 100644
--- a/spec/arel/unit/predicates/binary_spec.rb
+++ b/spec/arel/engines/sql/unit/predicates/binary_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Binary do
diff --git a/spec/arel/unit/predicates/equality_spec.rb b/spec/arel/engines/sql/unit/predicates/equality_spec.rb
index b595cdd247..2ab79d7028 100644
--- a/spec/arel/unit/predicates/equality_spec.rb
+++ b/spec/arel/engines/sql/unit/predicates/equality_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Equality do
diff --git a/spec/arel/unit/predicates/in_spec.rb b/spec/arel/engines/sql/unit/predicates/in_spec.rb
index 9107da9d4b..d977937e4e 100644
--- a/spec/arel/unit/predicates/in_spec.rb
+++ b/spec/arel/engines/sql/unit/predicates/in_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe In do
diff --git a/spec/arel/unit/primitives/attribute_spec.rb b/spec/arel/engines/sql/unit/primitives/attribute_spec.rb
index e512b40ebf..f37cd14370 100644
--- a/spec/arel/unit/primitives/attribute_spec.rb
+++ b/spec/arel/engines/sql/unit/primitives/attribute_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Attribute do
diff --git a/spec/arel/unit/primitives/expression_spec.rb b/spec/arel/engines/sql/unit/primitives/expression_spec.rb
index 92f300c4ee..0869d9e403 100644
--- a/spec/arel/unit/primitives/expression_spec.rb
+++ b/spec/arel/engines/sql/unit/primitives/expression_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Expression do
diff --git a/spec/arel/unit/primitives/value_spec.rb b/spec/arel/engines/sql/unit/primitives/value_spec.rb
index ba9a80bb49..f76323f32b 100644
--- a/spec/arel/unit/primitives/value_spec.rb
+++ b/spec/arel/engines/sql/unit/primitives/value_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Value do
diff --git a/spec/arel/unit/relations/alias_spec.rb b/spec/arel/engines/sql/unit/relations/alias_spec.rb
index 63c15cfeff..83b9113f6d 100644
--- a/spec/arel/unit/relations/alias_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/alias_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Alias do
diff --git a/spec/arel/unit/relations/array_spec.rb b/spec/arel/engines/sql/unit/relations/array_spec.rb
index d1c65c60a9..8d40858c5f 100644
--- a/spec/arel/unit/relations/array_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/array_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Array do
diff --git a/spec/arel/unit/relations/delete_spec.rb b/spec/arel/engines/sql/unit/relations/delete_spec.rb
index 23aca563f7..7a5e2b0088 100644
--- a/spec/arel/unit/relations/delete_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/delete_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Deletion do
diff --git a/spec/arel/unit/relations/group_spec.rb b/spec/arel/engines/sql/unit/relations/group_spec.rb
index 658c0ad406..b7279a23d9 100644
--- a/spec/arel/unit/relations/group_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/group_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Group do
diff --git a/spec/arel/unit/relations/insert_spec.rb b/spec/arel/engines/sql/unit/relations/insert_spec.rb
index 5ab3ef1299..dd1995cced 100644
--- a/spec/arel/unit/relations/insert_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/insert_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Insert do
diff --git a/spec/arel/unit/relations/join_spec.rb b/spec/arel/engines/sql/unit/relations/join_spec.rb
index 0e3e6ef16b..ea17f8106f 100644
--- a/spec/arel/unit/relations/join_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/join_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Join do
diff --git a/spec/arel/unit/relations/order_spec.rb b/spec/arel/engines/sql/unit/relations/order_spec.rb
index cb0f1de84c..ce97a4dd5e 100644
--- a/spec/arel/unit/relations/order_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/order_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Order do
diff --git a/spec/arel/unit/relations/project_spec.rb b/spec/arel/engines/sql/unit/relations/project_spec.rb
index d2d1fb3873..9d6b9fab06 100644
--- a/spec/arel/unit/relations/project_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/project_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Project do
diff --git a/spec/arel/unit/relations/relation_spec.rb b/spec/arel/engines/sql/unit/relations/relation_spec.rb
index 6a61f39966..9a5cfbff41 100644
--- a/spec/arel/unit/relations/relation_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/relation_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Relation do
diff --git a/spec/arel/unit/relations/skip_spec.rb b/spec/arel/engines/sql/unit/relations/skip_spec.rb
index 2c8f6ccadb..f8e5ceaad3 100644
--- a/spec/arel/unit/relations/skip_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/skip_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Skip do
diff --git a/spec/arel/unit/relations/table_spec.rb b/spec/arel/engines/sql/unit/relations/table_spec.rb
index 2779c0fe5d..6de49a9157 100644
--- a/spec/arel/unit/relations/table_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/table_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Table do
diff --git a/spec/arel/unit/relations/take_spec.rb b/spec/arel/engines/sql/unit/relations/take_spec.rb
index d6442fc9d1..1263ed4795 100644
--- a/spec/arel/unit/relations/take_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/take_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Take do
diff --git a/spec/arel/unit/relations/update_spec.rb b/spec/arel/engines/sql/unit/relations/update_spec.rb
index e0d7ddd295..f553490ef5 100644
--- a/spec/arel/unit/relations/update_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/update_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Update do
diff --git a/spec/arel/unit/relations/where_spec.rb b/spec/arel/engines/sql/unit/relations/where_spec.rb
index 64f97c8135..5870b6b793 100644
--- a/spec/arel/unit/relations/where_spec.rb
+++ b/spec/arel/engines/sql/unit/relations/where_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Where do
diff --git a/spec/arel/unit/session/session_spec.rb b/spec/arel/engines/sql/unit/session/session_spec.rb
index c30ba6195f..c489984a61 100644
--- a/spec/arel/unit/session/session_spec.rb
+++ b/spec/arel/engines/sql/unit/session/session_spec.rb
@@ -1,4 +1,4 @@
-require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper')
+require File.join(File.dirname(__FILE__), '..', '..', '..', '..', '..', 'spec_helper')
 
 module Arel
   describe Session do