Fix flaky transmission_interface tests by making them deterministic. (#…

…1665)

(cherry picked from commit ace8416)

# Conflicts:
#	transmission_interface/test/random_generator_utils.hpp

transmission_interface/include/transmission_interface/four_bar_linkage_transmission.hpp

@@ -288,7 +288,7 @@ inline void FourBarLinkageTransmission::actuator_to_joint()
 
     joint_eff[0].set_value(jr[0] * act_eff[0].get_value() * ar[0]);
     joint_eff[1].set_value(
-      jr[1] * (act_eff[1].get_value() * ar[1] - act_eff[0].get_value() * ar[0] * jr[0]));
+      jr[1] * (act_eff[1].get_value() * ar[1] - jr[0] * act_eff[0].get_value() * ar[0]));
   }
 }
 

transmission_interface/test/random_generator_utils.hpp

@@ -26,12 +26,18 @@ using std::vector;
 /// \brief Generator of pseudo-random double in the range [min_val, max_val].
 // NOTE: Based on example code available at:
 // http://stackoverflow.com/questions/2860673/initializing-a-c-vector-to-random-values-fast
+// Use a user specified seed instead of system time for deterministic tests
 struct RandomDoubleGenerator
 {
 public:
-  RandomDoubleGenerator(double min_val, double max_val) : min_val_(min_val), max_val_(max_val)
+  RandomDoubleGenerator(double min_val, double max_val, unsigned int seed = 1234)
+  : min_val_(min_val), max_val_(max_val)
   {
+<<<<<<< HEAD
     srand(time(nullptr));
+=======
+    srand(seed);
+>>>>>>> ace8416 (Fix flaky transmission_interface tests by making them deterministic. (#1665))
   }
   double operator()()
   {