Fix Rollbar::Util.deep_merge so it has default values for arguments

lib/rollbar/util.rb

@@ -66,10 +66,13 @@ def self.deep_copy(obj)
     end
 
     def self.deep_merge(hash1, hash2)
+      hash1 ||= {}
+      hash2 ||= {}
+
       hash2.each_key do |k|
-        if hash1[k].is_a? ::Hash and hash2[k].is_a? ::Hash
+        if hash1[k].is_a?(::Hash) && hash2[k].is_a?(::Hash)
           hash1[k] = deep_merge(hash1[k], hash2[k])
-        elsif hash1[k].is_a? Array and hash2[k].is_a? Array
+        elsif hash1[k].is_a?(Array) && hash2[k].is_a?(Array)
           hash1[k] += deep_copy(hash2[k])
         elsif hash2[k]
           hash1[k] = deep_copy(hash2[k])

spec/rollbar/util_spec.rb

@@ -0,0 +1,19 @@
+require 'spec_helper'
+
+require 'rollbar/util'
+
+describe Rollbar::Util do
+  describe '.deep_merge' do
+    context 'with nil arguments' do
+      let(:data) do
+        { :foo => :bar }
+      end
+
+      it 'doesnt fail and returns same hash' do
+        result = Rollbar::Util.deep_merge(nil, data)
+
+        expect(result).to be_eql(data)
+      end
+    end
+  end
+end

spec/rollbar_spec.rb

@@ -2,7 +2,6 @@
 
 require 'logger'
 require 'socket'
-require 'spec_helper'
 require 'girl_friday'
 require 'redis'
 require 'active_support/core_ext/object'
@@ -14,6 +13,8 @@
 rescue LoadError
 end
 
+require 'spec_helper'
+
 describe Rollbar do
   let(:notifier) { Rollbar.notifier }
   before do