CODEWITHSUNDEEP
c++unit-testingassertcatch-unit-test
tommyk
tommyk

Reputation: 3307

How to bypass assert in unit test in Debug mode?

In a test case I would like to test a function which in debug mode generates an assertion for invalid input. This unfortunately stops Catch test runner. Is there any way to bypass this assertion so that the test runner keeps going ?

Here is my test case:

 SCENARIO("Simple test case", "[tag]") {
    GIVEN("some object") {
        MyObject myobject;

        WHEN("object is initialized with invalid data") {
            // method init generates an assertion when parameters are invalid
            bool result = myObject.init(nullptr, nullptr, nullptr, nullptr);
            REQUIRE(false == result);

            THEN("data processing can't be started") {
            }
        }
    }
}

Upvotes: 1

Views: 990

Answers (1)

Adrian Colomitchi
Adrian Colomitchi

Reputation: 3992

Usually assert is a macro doing something like 

#define assert(e) ((void) ((e) \
  ? 0 
  : (void)printf ("%s:%u: failed assertion `%s'\n",  __FILE__, __LINE__, #e),
    abort(), // <-- this aborts you program after printf's above
    0        
)

and this macro is enabled in debug builds. For more specifics, look into your standard assert.h

So, if you have a binary library against which you link your test cases, you will need to tell the dev team that, unless they gave you a release build with no asserts enabled, you won't be able to unit-test their API for negative test cases.

If you need to test a header-only library or you compile against the source code to be tested, you'll need to

  1. compile your test cases/suite with -DNDEBUG; and/or
  2. define your own assert macro (e,g. to throw an error which you'll catch) and hope that your specific assert.h will test if already defined and won't try to define it again (again, look for specifics in your compiler/std libs assert.h header)

Upvotes: 1

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