Add unit tests for the scheduler

luprex/core/cpp/sched.hpp

@@ -24,6 +24,8 @@ public:
     }
 
     bool operator < (const SchedEntry &other) const;
+
+    std::string debug_string() const;
 };
 
 class Schedule {
@@ -32,7 +34,9 @@ private:
 public:
     void add(int64_t clk, int64_t thid, int64_t plid);
     bool ready(int64_t clk) const;
+    bool empty() const { return schedule_.empty(); }
     SchedEntry pop();
+    std::string debug_string();
 
     void serialize(StreamBuffer *sb);
     void deserialize(StreamBuffer *sb);