fix spurious rare failures in profile handler unittest

It's method of verifying that cpu profiling ticks happens is
inherently brittle. It sleeps certain time and then checks if ticks
happened during that time. And sleeping is by wall clock time. But due
to cpu scheduling being unpredictable, it is not impossible to see no
ticks even waiting 200 ms. We improve the issue by having the code
loop a bit until it seeks ticks happen.

1 files changed, 13 insertions, 2 deletions

diff --git a/src/tests/profile-handler_unittest.cc b/src/tests/profile-handler_unittest.cc
index 0bc2594..148ec4a 100644
--- a/src/tests/profile-handler_unittest.cc
+++ b/src/tests/profile-handler_unittest.cc
@@ -272,10 +272,21 @@ class ProfileHandlerTest : public ::testing::Test {
     uint64_t interrupts_before = GetInterruptCount();
     // Sleep for a bit and check that tick counter is making progress.
     int old_tick_count = tick_counter;
+    int new_tick_count;
+    uint64_t interrupts_after;
     Delay(kSleepInterval);
-    int new_tick_count = tick_counter;
-    uint64_t interrupts_after = GetInterruptCount();
     if (FLAGS_test_profiler_enabled) {
+      // The "sleep" check we do here is somewhat inherently
+      // brittle. But we can repeat waiting a bit more to ensure that
+      // ticks do occur.
+      for (int i = 10; i > 0; i--) {
+        new_tick_count = tick_counter;
+        interrupts_after = GetInterruptCount();
+        if (new_tick_count > old_tick_count && interrupts_after > interrupts_before) {
+          break;
+        }
+        Delay(kSleepInterval);
+      }
       EXPECT_GT(new_tick_count, old_tick_count);
       EXPECT_GT(interrupts_after, interrupts_before);
     } else {