modification for testability caused a panic when client tries to connect

to unknown agent.

pkg/server/matchmaker/matchmaker.go

@@ -119,7 +119,9 @@ func (converge *MatchMaker) Connect(wsProxyMode bool,
 
 	client, err := converge.admin.AddClient(publicId, conn)
 	cleanUpFunc := func() {
-		converge.admin.RemoveClient(client)
+		if client != nil {
+			converge.admin.RemoveClient(client)
+		}
 		converge.logStatus()
 	}
 	defer func() {

pkg/server/matchmaker/matchmaker_test.go

@@ -171,6 +171,14 @@ func (s *MatchMakerTestSuite) Test_singleAgentAndClient() {
 	s.checkState(1, 0)
 }
 
+func (s *MatchMakerTestSuite) Test_ConnectCLientToUnknownAgent() {
+	publicId := models.RendezVousId("abc")
+
+	client, err := s.connectClient(publicId)
+	s.NotNil(err)
+	s.Nil(client)
+}
+
 func (s *MatchMakerTestSuite) Test_multipleAgentsAndClients() {
 	agents := []string{"abc", "def", "ghi"}
 	clients := map[string]int{"abc": 3, "def": 2, "ghi": 5}
@@ -232,13 +240,12 @@ func (s *MatchMakerTestSuite) connectClient(publicId models.RendezVousId) (*Test
 			return nil
 		})
 
-	var err error = nil
 	if res[0] != nil {
-		err = res[0].(error)
+		return nil, res[0].(error)
 	}
 	client.publicId = publicId
 	client.clientId = clientId
-	return client, err
+	return client, nil
 }
 
 func (s *MatchMakerTestSuite) checkState(nAgents int, nClients int) {