             expect(value).to(equal(configuration))
             expect(value.requestCachePolicy).to(equal(configuration.requestCachePolicy))
           }
+          
+          it("sets additional HTTP headers") {
+            let headers = sessionConfiguration.value.HTTPAdditionalHeaders as? [String: String]
+            expect(headers).to(equal(Header.defaultHeaders))
+          }
         }
       }
     }

            let value = sessionConfiguration.value

            expect(value.identifier).to(equal("MalibuBackgroundConfiguration"))
          }
        }
      }

        describe("#value") {
          it("returns a correct NSURLSessionConfiguration") {
            let value = sessionConfiguration.value
            let expected = NSURLSessionConfiguration.defaultSessionConfiguration()
            expected.HTTPAdditionalHeaders = Header.defaultHeaders

            expect(value).to(equal(expected))
          }
          
          it("sets additional HTTP headers") {
            let headers = sessionConfiguration.value.HTTPAdditionalHeaders as? [String: String]
            expect(headers).to(equal(Header.defaultHeaders))
          }
        }
      }
