feat(loadFromVCAPServices): Service configuration factory.

Remove ConfigureService call from the BaseService constructor function.
Add a name field to the service interface.
Create a list of service entries and check for the service name within them before checking the keys to the service entry lists.
Update unit test to check that loadFromVCAPServices is looking for service credentials from the VCAP in the correct order.
loadFromVCAPServices checks for service names in keys of service entry lists before checking keys to service entry lists.

BREAKING CHANGE: NewBaseService constructor changes. `displayname`, and `serviceName` removed from construction function signature, since they are no longer used.

core/authenticator_factory_test.go

@@ -77,7 +77,7 @@ func TestGetAuthenticatorFromEnvironment2(t *testing.T) {
 }
 
 func TestGetAuthenticatorFromEnvironment3(t *testing.T) {
-	setTestVCAP()
+	setTestVCAP(t)
 
 	authenticator, err := GetAuthenticatorFromEnvironment("service-1")
 	assert.Nil(t, err)

core/base_service.go

@@ -64,7 +64,7 @@ type BaseService struct {
 
 // NewBaseService : This function will construct a new instance of the BaseService struct, while
 // performing validation on input parameters and service options.
-func NewBaseService(options *ServiceOptions, serviceName, displayName string) (*BaseService, error) {
+func NewBaseService(options *ServiceOptions) (*BaseService, error) {
 	if HasBadFirstOrLastChar(options.URL) {
 		return nil, fmt.Errorf(ERRORMSG_PROP_INVALID, "URL")
 	}
@@ -88,14 +88,10 @@ func NewBaseService(options *ServiceOptions, serviceName, displayName string) (*
 	// Set a default value for the User-Agent http header.
 	service.SetUserAgent(service.buildUserAgent())
 
-	err := service.ConfigureService(serviceName)
-	if err != nil {
-		return nil, err
-	}
-
 	return &service, nil
 }
 
+// ConfigureService configures the BaseService using external properties.
 func (service *BaseService) ConfigureService(serviceName string) error {
 	// Try to load service properties from external config.
 	serviceProps, err := getServiceProperties(serviceName)