Fix predicate

Author: urfeex

tests/test_external_control_program.cpp

@@ -116,7 +116,8 @@ class ExternalControlProgramTest : public ::testing::Test
   bool waitForConnectionCallback(int milliseconds = 100)
   {
     std::unique_lock<std::mutex> lk(connect_mutex_);
-    if (connect_cv_.wait_for(lk, std::chrono::milliseconds(milliseconds), connection_callback_ == true))
+    if (connect_cv_.wait_for(lk, std::chrono::milliseconds(milliseconds),
+                             [this]() { return connection_callback_ == true; }))
     {
       connection_callback_ = false;
       return true;