diff --git a/driver/tests/basic/main.cpp b/driver/tests/basic/main.cpp
index 586173eb..7377a860 100755
--- a/driver/tests/basic/main.cpp
+++ b/driver/tests/basic/main.cpp
@@ -185,8 +185,8 @@ int run_kernel_test(const kernel_arg_t& kernel_arg,
     int32_t curr = ((int32_t*)vx_host_ptr(staging_buf))[i];
     int32_t ref = i;
     if (curr != ref) {
-      std::cout << "error at result #" << i
-                << ": actual 0x" << curr << ", expected 0x" << ref << std::endl;
+      std::cout << "error at result #" << std::dec << i
+                << std::hex << ": actual 0x" << curr << ", expected 0x" << ref << std::endl;
       ++errors;
     }
   } 
diff --git a/driver/tests/demo/main.cpp b/driver/tests/demo/main.cpp
index 7261869c..68dc33e7 100644
--- a/driver/tests/demo/main.cpp
+++ b/driver/tests/demo/main.cpp
@@ -82,8 +82,8 @@ int run_test(const kernel_arg_t& kernel_arg,
       int ref = i + i; 
       int cur = buf_ptr[i];
       if (cur != ref) {
-        std::cout << "error at result #" << i
-                  << ": actual 0x" << cur << ", expected 0x" << ref << std::endl;
+        std::cout << "error at result #" << std::dec << i
+                  << std::hex << ": actual 0x" << cur << ", expected 0x" << ref << std::endl;
         ++errors;
       }
     }
diff --git a/driver/tests/stress/main.cpp b/driver/tests/stress/main.cpp
index 1329d5ba..1136c11e 100644
--- a/driver/tests/stress/main.cpp
+++ b/driver/tests/stress/main.cpp
@@ -114,7 +114,7 @@ void gen_input_data(uint32_t num_points) {
   test_data.resize(num_points);
   addr_table.resize(num_points + NUM_LOADS - 1);
 
-  for (uint32_t i = 0; i < test_data.size(); ++i) {
+  for (uint32_t i = 0; i < num_points; ++i) {
     float r = static_cast<float>(std::rand()) / RAND_MAX;
     test_data[i] = r;
   }