[API] Cleaned up the tests for predicate methods from commit 0116b2e

Removed the extra test files, and added a test case which test the predicate method availability and idenity.

Related: #133, #134

Author: karmi

elasticsearch-api/test/unit/exists?_document_test.rb

@@ -78,6 +78,11 @@ class ExistsTest < ::Test::Unit::TestCase
           end
         end
 
+        should "be aliased as predicate method" do
+          assert_nothing_raised do
+            subject.exists?(:index => 'foo', :type => 'bar', :id => '1') == subject.exists(:index => 'foo', :type => 'bar', :id => '1')
+          end
+        end
       end
 
     end

elasticsearch-api/test/unit/exists_document_test.rb

@@ -61,6 +61,11 @@ class IndicesExistsAliasTest < ::Test::Unit::TestCase
           end
         end
 
+        should "be aliased as predicate method" do
+          assert_nothing_raised do
+            subject.indices.exists_alias?(:name => 'foo') == subject.indices.exists_alias(:name => 'foo')
+          end
+        end
       end
 
     end

elasticsearch-api/test/unit/indices/exists?_test.rb

@@ -59,6 +59,11 @@ class IndicesExistsTest < ::Test::Unit::TestCase
           end
         end
 
+        should "be aliased as predicate method" do
+          assert_nothing_raised do
+            subject.indices.exists?(:index => 'foo') == subject.indices.exists(:index => 'foo')
+          end
+        end
       end
 
     end

elasticsearch-api/test/unit/indices/exists_alias?_test.rb

@@ -61,6 +61,11 @@ class IndicesExistsTypeTest < ::Test::Unit::TestCase
           end
         end
 
+        should "be aliased as predicate method" do
+          assert_nothing_raised do
+            subject.indices.exists_type?(:index => 'foo', :type => 'bar') == subject.indices.exists_type(:index => 'foo', :type => 'bar')
+          end
+        end
       end
 
     end