[rostest]Subscriber callback not being called even with getNumPublishers() > 1

edit

So I've the following class for using Fixture tests from gtest:

class DiagnosticsMsgParserTest : public ::testing::Test {
     public:
      DiagnosticsMsgParserTest() {
        diagnostic_sub_ = nh_.subscribe("diagnostics_agg", 100, &DiagnosticsMsgParserTest::diagnosticCB, this);
      }
      void SetUp() override {
        while (diagnostic_pub_.getNumPublishers() < 1 && ros::ok()) {
          ros::Duration(0.5).sleep();
        }
        ASSERT_TRUE(ros::ok());
        ASSERT_EQ(1, diagnostic_pub_.getNumPublishers());
        ros::spinOnce();
      };
      void TearDown() override {};
      void diagnosticCB(const diagnostic_msgs::DiagnosticArrayConstPtr& msg) {
        msg_ = *msg;
        EXPECT_GT(0, 1);  // just for debuggin, if callback is called this line will advertise
                                  // some error
      }

      ros::NodeHandle nh_;
      diagnostic_msgs::DiagnosticArray msg_;
      ros::Subscriber diagnostic_sub_;
    };

And the following testsuite:

TEST_F(DiagnosticsMsgParserTest, getParsedObject) {
  ros::spinOnce();
  const auto& parsed_objects = diagnostics_tools::DiagnosticsMsgsParser::parse(msg_);

  ASSERT_EQ(1, diagnostic_sub_.getNumPublishers());
  EXPECT_TRUE(ros::ok());
  EXPECT_EQ(2, msg_.status.size());

  ros::master::V_TopicInfo master_topics;
  ros::master::getTopics(master_topics);
  EXPECT_EQ(2, master_topics.size());
  EXPECT_EQ("foo", master_topics[3].name);
}

Well, diagnosticCB is never called, even when diagnostic_pub_.getNumPublishers() > 1 and ros::ok() (I've an aggregator_node included from the rostest file). You can see on bellow my test-results for this suite:

<testsuite name="DiagnosticsMsgParserTest" tests="1" failures="1" disabled="0" errors="0" time="0.68">
    <testcase name="getParsedObject" status="run" time="0.68" classname="DiagnosticsMsgParserTest">
      <failure message="/home/caioaamaral/Workspace/mccr_ws/src/elmo_gold_ros_pkgs/elmo_gold_diagnostics/test/test_diagnostics_msg_parser.cpp:49&#x0A;Value of: msg_.status.size()&#x0A;  Actual: 0&#x0A;Expected: 2" type=""><![CDATA[/home/caioaamaral/Workspace/mccr_ws/src/elmo_gold_ros_pkgs/elmo_gold_diagnostics/test/test_diagnostics_msg_parser.cpp:49
Value of: msg_.status.size()
  Actual: 0
Expected: 2]]></failure>
      <failure message="/home/caioaamaral/Workspace/mccr_ws/src/elmo_gold_ros_pkgs/elmo_gold_diagnostics/test/test_diagnostics_msg_parser.cpp:69&#x0A;Value of: master_topics.size()&#x0A;  Actual: 3&#x0A;Expected: 2" type=""><![CDATA[/home/caioaamaral/Workspace/mccr_ws/src/elmo_gold_ros_pkgs/elmo_gold_diagnostics/test/test_diagnostics_msg_parser.cpp:69
Value of: master_topics.size()
  Actual: 3
Expected: 2]]></failure>
      <failure message="/home/caioaamaral/Workspace/mccr_ws/src/elmo_gold_ros_pkgs/elmo_gold_diagnostics/test/test_diagnostics_msg_parser.cpp:70&#x0A;Value of: master_topics[1].name&#x0A;  Actual: &quot;/diagnostics_agg&quot;&#x0A;Expected: &quot;sad&quot;" type=""><![CDATA[/home/caioaamaral/Workspace/mccr_ws/src/elmo_gold_ros_pkgs/elmo_gold_diagnostics/test/test_diagnostics_msg_parser.cpp:70
Value of: master_topics[1].name
  Actual: "/diagnostics_agg"
Expected: "foo"]]></failure>
    </testcase>
  </testsuite>

It shows me that diagnostic_msgs::DiagnosticArray msg_ is never been filled by callback call, as it's empty and it didn't throw any error for EXPECT_GT(0, 1). Also, it shows that diagnostic_sub_ topic has at least one publisher advertised to it, and from strong textros::master::getTopics it shows that (by master_topics.size()) it has 3 topics being published at all, and one of then is indeed the "/diagnostics_agg".

There is no /diagnostics topic being advertised, but even there I was expecting to catch all "Stale" msgs from "/diagnostics_agg"

Does anyone have have some idea on how to make callback be called at all?