Attempt to deflake rendezvous tests

We see occasional failures on Github CI for this test where we haven't
gotten any agent strings back. This appears to be a race condition
between the server ack'ing the message and then saving the user agent
string. Move the ack after the save to ensure its there in the test.

Closes: #36 [via git-merge-pr]

rendezvous/client_test.go

@@ -33,7 +33,7 @@ func TestBasicClient(t *testing.T) {
 
 	gotAgents := ts.Agents()
 	expectAgents := [][]string{
-		[]string{version.AgentString, version.AgentVersion},
+		{version.AgentString, version.AgentVersion},
 	}
 
 	if !reflect.DeepEqual(gotAgents, expectAgents) {
@@ -131,7 +131,7 @@ func TestCustomUserAgent(t *testing.T) {
 
 	gotAgents := ts.Agents()
 	expectAgents := [][]string{
-		[]string{agentString, agentVersion},
+		{agentString, agentVersion},
 	}
 
 	if !reflect.DeepEqual(gotAgents, expectAgents) {

rendezvous/rendezvousservertest/rendezvousservertest.go

@@ -42,6 +42,8 @@ func NewServer() *TestServer {
 }
 
 func (ts *TestServer) Agents() [][]string {
+	ts.mu.Lock()
+	defer ts.mu.Unlock()
 	return ts.agents
 }
 
@@ -229,23 +231,24 @@ func (ts *TestServer) handleWS(w http.ResponseWriter, r *http.Request) {
 
 		switch m := msg.(type) {
 		case *msgs.Bind:
-			ackMsg(m.ID)
-
 			if sideID != "" {
+				ackMsg(m.ID)
 				errMsg(m.ID, m, fmt.Errorf("already bound"))
 				continue
 			}
 
 			if m.Side == "" {
+				ackMsg(m.ID)
 				errMsg(m.ID, m, fmt.Errorf("bind requires 'side'"))
 				continue
 			}
 
 			ts.mu.Lock()
 			ts.agents = append(ts.agents, m.ClientVersion)
 			ts.mu.Unlock()
-
 			sideID = m.Side
+
+			ackMsg(m.ID)
 		case *msgs.Allocate:
 			ackMsg(m.ID)