show an error in tests/hello_world_file.cpp if we can't open the file; closes #2389

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/hello_world_file.cpp b/tests/hello_world_file.cpp
index 71fb953b..97ea395e 100644
--- a/tests/hello_world_file.cpp
+++ b/tests/hello_world_file.cpp
@@ -1,6 +1,10 @@
 #include <stdio.h>
 int main() {
   FILE *file = fopen("tests/hello_world_file.txt", "rb");
+  if (!file) {
+    printf("cannot open file\n");
+    return 1;
+  }
   while (!feof(file)) {
     char c = fgetc(file);
     if (c != EOF) {