uORB: Unit test fix

The latency_test used to pass an object pointer as argv which
won't work in the posix port because it expects argv to be a
null terminated array of character pointers (which it makes a
copy of).

The test was refactored to use a singleton pattern and avoid
having to pass the object pointer to the thread.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/modules/uORB/uORBMain.cpp

@@ -90,7 +90,7 @@ uorb_main(int argc, char *argv[])
    */
   if (!strcmp(argv[1], "test"))
   {
-    uORBTest::UnitTest t;
+    uORBTest::UnitTest &t = uORBTest::UnitTest::instance();
     return t.test();
   }
 
@@ -99,7 +99,7 @@ uorb_main(int argc, char *argv[])
    */
   if (!strcmp(argv[1], "latency_test")) {
 
-    uORBTest::UnitTest t;
+    uORBTest::UnitTest &t = uORBTest::UnitTest::instance();
     if (argc > 2 && !strcmp(argv[2], "medium")) {
       return t.latency_test<struct orb_test_medium>(ORB_ID(orb_test_medium), true);
     } else if (argc > 2 && !strcmp(argv[2], "large")) {
@@ -118,7 +118,5 @@ uorb_main(int argc, char *argv[])
   }
 
   usage();
-  errx(-EINVAL, "unrecognized command, try 'start', 'test', 'latency_test' or 'status'");
+  return -EINVAL;
 }
-
-

src/modules/uORB/uORBTest_UnitTest.cpp

@@ -36,6 +36,12 @@
 #include <px4_config.h>
 #include <px4_time.h>
 
+uORBTest::UnitTest &uORBTest::UnitTest::instance()
+{
+	static uORBTest::UnitTest t;
+	return t;
+}
+
 int uORBTest::UnitTest::pubsublatency_main(void)
 {
   /* poll on test topic and output latency */
@@ -276,12 +282,8 @@ int uORBTest::UnitTest::test_note(const char *fmt, ...)
   return OK;
 }
 
-int uORBTest::UnitTest::pubsubtest_threadEntry( char* const* data )
+int uORBTest::UnitTest::pubsubtest_threadEntry(char* const argv[])
 {
-  uORBTest::UnitTest* t = (uORBTest::UnitTest*) data;
-  if( data != nullptr )
-  {
-    return t->pubsublatency_main();
-  }
-  return uORB::ERROR;
+  uORBTest::UnitTest &t = uORBTest::UnitTest::instance();
+  return t.pubsublatency_main();
 }

src/modules/uORB/uORBTest_UnitTest.hpp

@@ -68,15 +68,22 @@ class uORBTest::UnitTest
 {
 public:
 
+  // Singleton pattern
+  static uORBTest::UnitTest &instance();
+  ~UnitTest() {}
   int test();
   template<typename S> int latency_test(orb_id_t T, bool print);
   int info();
 
 private:
-  static int pubsubtest_threadEntry( char* const* argv );
+  UnitTest() : pubsubtest_passed(false), pubsubtest_print(false) {}
+
+  // Disallow copy
+  UnitTest(const uORBTest::UnitTest &) {};
+  static int pubsubtest_threadEntry(char* const argv[]);
   int pubsublatency_main(void);
-  bool pubsubtest_passed = false;
-  bool pubsubtest_print = false;
+  bool pubsubtest_passed;
+  bool pubsubtest_print;
   int pubsubtest_res = OK;
 
   int test_fail(const char *fmt, ...);
@@ -93,14 +100,16 @@ int uORBTest::UnitTest::latency_test(orb_id_t T, bool print)
 
   int pfd0 = orb_advertise(T, &t);
 
-  char * const args[2] = { (char* const) this, 0 };
+  char * const args[1] = { NULL };
 
   pubsubtest_print = print;
-
   pubsubtest_passed = false;
 
   /* test pub / sub latency */
 
+  // Can't pass a pointer in args, must be a null terminated
+  // array of strings because the strings are copied to
+  // prevent access if the caller data goes out of scope
   int pubsub_task = px4_task_spawn_cmd("uorb_latency",
                SCHED_DEFAULT,
                SCHED_PRIORITY_MAX - 5,