For any test that you want to perform, you write a script located in
test/recipes/, named {nn}-test_{name}.t,
where {nn} is a two digit number and
{name} is a unique name of your choice.
Please note that if a test involves a new testing executable, you will need to do some additions in test/build.info. Please refer to the section "Changes to test/build.info" below.
A test executable is named test/{name}test.c
A test recipe is named test/recipes/{nn}-test_{name}.t, where {nn} is a two
digit number and {name} is a unique name of your choice.
The number {nn} is (somewhat loosely) grouped as follows:
00-04  sanity, internal and essential API tests
05-09  individual symmetric cipher algorithms
10-14  math (bignum)
15-19  individual asymmetric cipher algorithms
20-24  openssl commands (some otherwise not tested)
25-29  certificate forms, generation and verification
30-35  engine and evp
60-79  APIs:
   60  X509 subsystem
   61  BIO subsystem
   65  CMP subsystem
   70  PACKET layer
80-89  "larger" protocols (CA, CMS, OCSP, SSL, TSA)
90-98  misc
99     most time consuming tests [such as test_fuzz]
A script that just runs a program looks like this:
#! /usr/bin/env perl
use OpenSSL::Test::Simple;
simple_test("test_{name}", "{name}test", "{name}");
{name} is the unique name you have chosen for your test.
The second argument to simple_test is the test executable, and simple_test
expects it to be located in test/
For documentation on OpenSSL::Test::Simple,
do perldoc util/perl/OpenSSL/Test/Simple.pm.
For more complex tests, you will need to read up on Test::More and
OpenSSL::Test.  Test::More is normally preinstalled, do man Test::More for
documentation.  For OpenSSL::Test, do perldoc util/perl/OpenSSL/Test.pm.
A script to start from could be this:
#! /usr/bin/env perl
use strict;
use warnings;
use OpenSSL::Test;
setup("test_{name}");
plan tests => 2;                # The number of tests being performed
ok(test1, "test1");
ok(test2, "test1");
sub test1
{
    # test feature 1
}
sub test2
{
    # test feature 2
}
Whenever a new test involves a new test executable you need to do the following (at all times, replace {NAME} and {name} with the name of your test):
add {name} to the list of programs under PROGRAMS_NO_INST
create a three line description of how to build the test, you will have to modify the include paths and source files if you don't want to use the basic test framework:
SOURCE[{name}]={name}.c INCLUDE[{name}]=.. ../include ../apps/include DEPEND[{name}]=../libcrypto libtestutil.a
#include "testutil.h"
static int my_test(void)
{
    int testresult = 0;                 /* Assume the test will fail    */
    int observed;
    observed = function();              /* Call the code under test     */
    if (!TEST_int_eq(observed, 2))      /* Check the result is correct  */
        goto end;                       /* Exit on failure - optional   */
    testresult = 1;                     /* Mark the test case a success */
end:
    cleanup();                          /* Any cleanup you require      */
    return testresult;
}
int setup_tests(void)
{
    ADD_TEST(my_test);                  /* Add each test separately     */
    return 1;                           /* Indicates success.  Return 0 */
                                        /* to produce an error with a   */
                                        /* usage message and -1 for     */
                                        /* failure to set up with no    */
                                        /* usage message.               */
}
You should use the TEST_xxx macros provided by testutil.h to test all failure
conditions.  These macros produce an error message in a standard format if the
condition is not met (and nothing if the condition is met).  Additional
information can be presented with the TEST_info macro that takes a printf
format string and arguments.  TEST_error is useful for complicated conditions,
it also takes a printf format string and argument.  In all cases the TEST_xxx
macros are guaranteed to evaluate their arguments exactly once.  This means
that expressions with side effects are allowed as parameters.  Thus,
if (!TEST_ptr(ptr = OPENSSL_malloc(..)))
works fine and can be used in place of:
ptr = OPENSSL_malloc(..);
if (!TEST_ptr(ptr))
The former produces a more meaningful message on failure than the latter.
Note that the test infrastructure automatically sets up all required environment
variables (such as OPENSSL_MODULES, OPENSSL_CONF, etc.) for the tests.
Individual tests may choose to override the default settings as required.