NAME

     zt_claim — structure capturing unevaluated assertion

SYNOPSIS

     #include <zt.h>

     typedef struct zt_claim { ... } zt_claim;

     Type                              Member            Description
     struct zt_verifier *(*)(void)     make_verifier     Verifier factory
     zt_value[3]                       args              verifier arguments
     zt_location                       location          origin of the claim

DESCRIPTION

     zt_claim binds a verifier factory function with concrete arguments. This allows the entire claim to be
     passed around and evaluated on demand. In case of failure the location where the claim was made can be
     referenced for construction of error messages.

IMPLEMENTATION NOTES

     The verification system is comprised of the following chain of cooperating elements. For example a trivial
     integer relationship assertion behaves as follows.  ZT_CMP_INT(), or another similar macro, invokes
     zt_cmp_int(), providing source code location as zt_location, and packaging specific types into common
     variant type zt_value.  The result is a zt_claim which is then passed to zt_assert() or zt_check() for
     evaluation.

     The roles of all the essential types and functions is summarized below.

     •   zt_value captures values expressed in a test case

     •   zt_claim transports up to three values and an opaque verifier

     •   zt_check() and zt_assert() validate the claim by instantiating zt_verifier.

     •   zt_verifier (private) wraps a verification function, including the arity and expected kind of each
         argument.

     •   zt_arg_info (private) pairs expected argument kind with a customized error message used on kind
         mismatch.

     •   zt_verify_claim() (private) ensures verifier function arity and argument kind matches what is encoded
         in the claim and invokes the verifier function.

     •   The specific verifier function inspects the argument and performs the actual verification of the
         desired property that the test is measuring.

     •   zt_test (private) keeps track of test outcome, provides a stream for writing error messages and assists
         in performing non-local exit.

SEE ALSO

     zt_assert(3), zt_check(3)

HISTORY

     zt_claim first appeared in libzt 0.1

BUGS

     Part of the API is private which prevents third party verification functions from being written. This is
     done on purpose to to allow for some more experimentation before stabilizing the interface.

AUTHORS

     Zygmunt Krynicki <me@zygoon.pl>