diff --git a/test/test-hrtime.c b/test/test-hrtime.c
index e7309804..41f9f1c9 100644
--- a/test/test-hrtime.c
+++ b/test/test-hrtime.c
@@ -23,6 +23,10 @@
 #include "task.h"
 
 
+/*
+ * We expect the amount of time passed to be at least one us plus two system
+ * calls. Therefore checking that at least a microsecond has elapsed is safe.
+ */
 TEST_IMPL(hrtime) {
   uint64_t a, b, diff;
 
@@ -33,5 +37,7 @@ TEST_IMPL(hrtime) {
   diff = b - a;
 
   printf("diff = %llu\n", diff);
-  ASSERT(b - a >= NANOSEC / MILLISEC);
+
+  ASSERT(diff >= NANOSEC / MICROSEC);
+  return 0;
 }