Assert that a predicate evaluates to true.

Used in: A test function body, the constructor or destructor of a fixture, or a function called from them. See TEST(name, ...).

Requirement: pred is callable with ... as its parameter list, and returns a value that can be evaluated as a bool.

... may be 0 to 9 expressions.

The assertion succeeds if, and only if, bool(pred(...)) returns a value that compares equal to true.

On success the test function continues without side effects.

On failure the test is terminated with an error report. The report includes the predicate and parameter list text, and the parameter values that are output streamable have a text representation of their value, and a byte by byte hex dump for the others. If the pred itself has an output stream operator, the output of it is included for extra information.

Example: The test program

     
     #include <crpcut.hpp>
     #include <cstring>
     
     TEST(assert_pred_succeeds)
     {
       char non_zero_string[] = "s";
       ASSERT_PRED(std::strlen, non_zero_string);
     }
     
     TEST(assert_pred_fails)
     {
       char haystack[] = "a haystack string";
       char needle[] = "pqr";
       ASSERT_PRED(std::strspn, haystack, needle);
     }
     
     int main(int argc, char *argv[])
     {
       return crpcut::run(argc, argv);
     }

      

reports one failed test:

     FAILED: assert_pred_fails
     phase="running"  --------------------------------------------------------------
     /home/bjorn/devel/crpcut/doc-src/samples/assert_pred_fails.cpp:41
     ASSERT_PRED(std::strspn, haystack, needle)
       param1 = a haystack string
       param2 = pqr
     
     -------------------------------------------------------------------------------
     ===============================================================================
     Total 2 test cases selected
     UNTESTED : 0
     PASSED   : 1
     FAILED   : 1

      

See also: crpcut::match<matcher>(...) for floating point comparisons ( crpcut::abs_diff, crpcut::relative_diff, crpcut::ulps_diff,) for matching regular expressions ( crpcut::regex,) and for string collation (crpcut::collate.)

	Tip
	If you have a compiler that supports C++0x lambda expressions, lambdas make excellent predicates. const char *refstr = get_from_a_function(); ASSERT_PRED([](const char *p) { return ::strcmp(p, "key") == 0; }, refstr);