diff --git a/revid/senders_test.go b/revid/senders_test.go
index 1c516e16..360e540e 100644
--- a/revid/senders_test.go
+++ b/revid/senders_test.go
@@ -270,6 +270,8 @@ func TestNewMultiSender(t *testing.T) {
 	}
 }
 
+// dummyLoadSender is a loadSender implementation that allows us to simulate
+// the behaviour of a loadSender and check that it performas as expected.
 type dummyLoadSender struct {
 	data        []byte
 	buf         [][]byte
@@ -277,15 +279,20 @@ type dummyLoadSender struct {
 	failHandled bool
 }
 
+// newDummyLoadSender returns a pointer to a new dummyLoadSender.
 func newDummyLoadSender(fail bool) *dummyLoadSender {
 	return &dummyLoadSender{failOnSend: fail, failHandled: true}
 }
 
+// load takes a byte slice and assigns it to the dummyLoadSenders data slice.
 func (s *dummyLoadSender) load(d []byte) error {
 	s.data = d
 	return nil
 }
 
+// send will append to dummyLoadSender's buf slice, only if failOnSend is false.
+// If failOnSend is set to true, we expect that data sent won't be written to
+// the buf simulating a failed send.
 func (s *dummyLoadSender) send() error {
 	if !s.failOnSend {
 		s.buf = append(s.buf, s.data)
@@ -294,17 +301,23 @@ func (s *dummyLoadSender) send() error {
 	return errSendFailed
 }
 
+// release sets dummyLoadSender's data slice to nil. data can be checked to see
+// if release has been called at the right time.
 func (s *dummyLoadSender) release() {
 	s.data = nil
 }
 
 func (s *dummyLoadSender) close() error { return nil }
 
+// handleSendFail simply sets the failHandled flag to true. This can be checked
+// to see if handleSendFail has been called by the multiSender at the right time.
 func (s *dummyLoadSender) handleSendFail(err error) error {
 	s.failHandled = true
 	return nil
 }
 
+// TestMultiSenderWrite checks that we can do basic writing to multiple senders
+// using the multiSender.
 func TestMultiSenderWrite(t *testing.T) {
 	senders := []loadSender{
 		newDummyLoadSender(false),