[Coverity CID :203505]Integer handling issues in /tests/lib/fdtable/src/main.c

[aasthagr]

Static code scan issues seen in File: /tests/lib/fdtable/src/main.c
Category: Integer handling issues
Function: test_z_reserve_fd
Component: Tests
CID: 203505
Please fix or provide comments to square it off in coverity in the link: https://scan9.coverity.com/reports.htm#v32951/p12996

[aasthagr]

*** CID 203505:  Integer handling issues  (NEGATIVE_RETURNS)
/tests/lib/fdtable/src/main.c: 18 in test_z_reserve_fd()
12     void test_z_reserve_fd(void)
13     {
14     	int fd = z_reserve_fd(); /* function being tested */
15     
16     	zassert_equal(fd >= 0, true, "fd < 0");
17     
>>>     CID 203505:  Integer handling issues  (NEGATIVE_RETURNS)
>>>     "fd" is passed to a parameter that cannot be negative.
18     	z_free_fd(fd);
19     }
20     
21     void test_z_get_fd_obj_and_vtable(void)
22     {
23     	const struct fd_op_vtable *vtable;

[aescolar]

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