[pzstd] Add logging statements to tests

contrib/pzstd/utils/test/ThreadPoolTest.cpp

@@ -10,6 +10,7 @@
 
 #include <gtest/gtest.h>
 #include <atomic>
+#include <iostream>
 #include <thread>
 #include <vector>
 
@@ -34,16 +35,19 @@ TEST(ThreadPool, AllJobsFinished) {
   std::atomic<unsigned> numFinished{0};
   std::atomic<bool> start{false};
   {
+    std::cerr << "Creating executor" << std::endl;
     ThreadPool executor(5);
     for (int i = 0; i < 10; ++i) {
       executor.add([ &numFinished, &start ] {
         while (!start.load()) {
-          // spin
+          std::this_thread::yield();
         }
         ++numFinished;
       });
     }
+    std::cerr << "Starting" << std::endl;
     start.store(true);
+    std::cerr << "Finishing" << std::endl;
   }
   EXPECT_EQ(10, numFinished.load());
 }