extend ::Hash with #set_or_incr and #merge_and_incr methods

spec/core_ext/hash_spec.rb

@@ -0,0 +1,20 @@
+require "spec_helper"
+
+describe Hash do
+  
+  it "should #set_or_incr values" do
+    hash = {:count => 1}
+    hash.set_or_incr(:sum, 3)
+    hash.should == {:count => 1, :sum => 3}
+    hash.set_or_incr(:count, 4)
+    hash.should == {:count => 5, :sum => 3}
+  end
+  
+  it "should #merge_and_incr hashes" do
+    hash     = {:count => 1, :city => 'hell', :sum => 3, :name => 'john'}
+    new_hash = {:count => 3, :city => 'slum', :views => 2}
+    hash.merge_and_incr(new_hash)
+    hash.should == {:count => 4, :sum => 3, :views => 2, :city => 'slum', :name => 'john'}
+  end
+  
+end