3 files changed, 70 insertions, 0 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..14fd7ab21b
--- /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
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..af91f8b51b
--- /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
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..a8a15ce4e3
--- /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