fix data race in test

Author: nghialv

Diff for: clientconn_test.go

@@ -359,24 +359,43 @@ func TestPreventReaddAddrConnAfterDeletingByBalancer(t *testing.T) {
 			time.Sleep(10 * time.Millisecond)
 		}
 	}
-	if len(cc.conns) != 2 {
-		t.Fatalf("Number of addConns, want %d, got %d", 2, len(cc.conns))
+
+	getConnCount := func() int {
+		cc.mu.RLock()
+		defer cc.mu.RUnlock()
+		return len(cc.conns)
+	}
+
+	getAddrCount := func() int {
+		cc.mu.RLock()
+		defer cc.mu.RUnlock()
+		return len(cc.addrs)
+	}
+
+	connCount := getConnCount()
+	if connCount != 2 {
+		t.Fatalf("Number of addConns, want %d, got %d", 2, connCount)
 	}
-	if len(cc.addrs) != 2 {
-		t.Fatalf("Number of addrs, want %d, got %d", 2, len(cc.addrs))
+
+	addrCount := getAddrCount()
+	if addrCount != 2 {
+		t.Fatalf("Number of addrs, want %d, got %d", 2, addrCount)
 	}
+
 	// Delete servers[1] by balancer
 	u := &naming.Update{
 		Op:   naming.Delete,
 		Addr: "localhost:" + servers[1].port,
 	}
 	r.w.inject([]*naming.Update{u})
 	// Wait until the addrConn of services[1] is deleted
-	for len(cc.conns) != 1 {
+	for getConnCount() != 1 {
 		time.Sleep(10 * time.Millisecond)
 	}
-	if len(cc.addrs) != 1 {
-		t.Fatalf("Number of addrs, want %d, got %d", 1, len(cc.addrs))
+
+	addrCount = getAddrCount()
+	if addrCount != 1 {
+		t.Fatalf("Number of addrs, want %d, got %d", 1, addrCount)
 	}
 
 	// Call resetAddrConn (ex: goaway)
@@ -385,7 +404,8 @@ func TestPreventReaddAddrConnAfterDeletingByBalancer(t *testing.T) {
 		t.Fatalf("Failed to reset addrConn: %v", err)
 	}
 
-	if len(cc.conns) != 1 {
-		t.Fatalf("Number of addConns, want %d, got %d", 1, len(cc.conns))
+	connCount = getConnCount()
+	if connCount != 1 {
+		t.Fatalf("Number of addConns, want %d, got %d", 1, connCount)
 	}
 }