Kill all mutants in Zero::Request::Parameter

I've also changed "extract_query_params" because it does not matter, if the
query string it empty or not for the "parse_string" method.

lib/zero/request/parameter.rb

@@ -79,14 +79,15 @@ module Zero
       # extracts the key value pairs from the environment
       # @return Hash all key value pairs from query string
       def extract_query_params(environment)
-        return {} if environment[ENV_KEY_QUERY].length == 0
         parse_string(environment[ENV_KEY_QUERY])
       end
 
       # extracts the key value pairs from the body
       # @return Hash all key value pairs from the payload
       def extract_payload_params(environment)
-        return {} unless PAYLOAD_CONTENT_TYPES.include?(environment[ENV_KEY_CONTENT_TYPE])
+        unless PAYLOAD_CONTENT_TYPES.include?(environment[ENV_KEY_CONTENT_TYPE])
+          return {}
+        end
         parse_string(environment[ENV_KEY_PAYLOAD].read)
       end
 

spec/unit/request/parameter/custom_spec.rb

@@ -15,4 +15,9 @@ describe Zero::Request::Parameter, '#custom' do
 
     expect(subject.custom['foo']).to eq('latest')
   end
+
+  it 'is empty if no custom parameter is set' do
+    expect(subject.custom).to eq({})
+    expect(env['zero.params.custom']).to eq({})
+  end
 end

spec/unit/request/parameter/initialize_spec.rb

@@ -3,7 +3,8 @@ require 'spec_helper'
 describe Zero::Request::Parameter, '#initialize' do
   subject { Zero::Request::Parameter.new(env) }
   let(:env) { EnvGenerator.get('/get', {
-    'zero.params.custom' => {'foo' => 'bar'} }) }
+    'zero.params.custom' => {'foo' => 'bar'}
+  }) }
 
   it 'does not overwrite parameters' do
     subject

spec/unit/request/parameter/payload_spec.rb

@@ -30,4 +30,14 @@ describe Zero::Request::Parameter, '#payload' do
     end
     its(:payload) { should == {'bar' => 'foo bar'} }
   end
+
+  # TODO behaves like this, but is this really good like this?
+  context 'with a post body and content type application/json' do
+    let(:env) do
+      EnvGenerator.post('/foo', {
+        :input => '"foobar"', 'CONTENT_TYPE' => 'application/json'
+      })
+    end
+    its(:payload) { should == {} }
+  end
 end