test case for fread() errors in C

In one C application I'm maintaining, there are a number of calls to fread().

The return value is checked for the number of bytes read, and stops when it reaches 0, meaning the file/stream end has been reached.

Now, that's not completely correct. fread() may also return 0 if an error happens. A way to check for that condition is to call feof() for example.

I can certainly add all these tests everywhere fread() is invoked. But that's not the point : it would be some kind of "blind fix". I need a test case to observe and repeat the problem, and observe the correction as part of CI tests.

So far, I have found none. I have much less problems for fwrite(), where it's comparatively easier to create problems, but for fread(), I haven't found a reliable way to test issues without also impacting fopen(), which is a completely different situation already pretty well tested.

Any suggestion welcomed.