Run clang-tidy on project with headers - c

Question

I have a project that I recently split up into headers + sources, and now clang-tidy wont "actually" check my test files that include these headers. Below is an example of the situation:
File Structure:
src/
main.c
a.h
a.c
test/
test.c
Code:
// src/main.c
#include "src/a.h"
int main(void) {
a();
return 0;
}
// src/a.h
void a(void);
// src/a.c
#include <stdlib.h>
#include "src/a.h"
void a(void) {
malloc(1); // obvious memory leak
}
// test/test.c
#include "src/a.h"
int main(void) {
// do test stuff
a();
return 0;
}
Compile src: cc src/*.c -I. -o main
Compile test: cc src/a.c test/test.c -I. -o test
Running does nothing, but the code does compile.
Then, I run the code through clang-tidy:
clang-tidy src/* -- -I.
This works:
1 warning generated.
1 warning generated.
1 warning generated.
/src/a.c:8:1: warning: Potential memory leak [clang-analyzer-unix.Malloc]
}
^
/src/a.c:7:2: note: Memory is allocated
malloc(1);
^
/src/a.c:8:1: note: Potential memory leak
}
^
But if I do:
clang-tidy test/test.c -- -I.
Nothing is outputed (ive tried to add the header-filter flag as well).
I pressume that the headers are being included, and the test code has no knowledge of the source. So, how can I make sure my tests are actually being checked if this is the case? These headers and sources are in my project, so it would only make sense that clang-tidy would be able to pick up on this?
Edit:
I can do the following, and it seems to only partially fix the problem:
// test/test.c
#include "src/a.h"
#include "src/a.c" //added this line
int main(void) {
// do test stuff
a();
return 0;
}
Now, clang-tidy picks up on the actual .c file, and thus finds the issue. But, now I cant compile my code. There is supposed to be a __clang_analyzer__ define that gets set when the code is being analyzed, but it seems to just ignore it:
#ifdef __clang_analyzer__
#include "src/a.c" // doesnt include file, thus the malloc() call is never detected
#endif

Answer 1

clang-tidy is only a static analyser tool, said differently a linter. It does not try to build or run an executable: it just analyses the C source files it has been given after processing the include parts.
Static analysis and testing are different parts of a quality assurance process:
the former only reads source files searching for common errors and runs nothing
the latter runs (parts of) a code base with known inputs and controls that outputs have expected values
That means that clang-tidy is expected to be run on your main sources, not only on the test ones.
To be clear, it can make sense to pass test sources to the linter, because they could contain problems that clang-tidy would detect. But only running clang-tidy on the test folder will not detect problem in main folder, whatever the coverage.