unittests: basic docs

tests/unit/README

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+Unit tests
+==========
+
+The goal is to add tests for *ALL* functions in libcurl. If functions are too
+big and complicated, we should split them into smaller and testable ones.
+
+Build Unit Tests
+================
+
+'./configure --enable-debug' is required for the unit tests to build. To
+enable unit tests, there will be a separate static libcurl built that will be
+used exclusively for linking unit test programs. Just build everything as
+normal, and then you can run the unit test cases as well.
+
+Run Unit Tests
+==============
+
+Unit tests are run as part of the regular test suite. If you have built
+everything to run unit tests, to can do 'make test' at the root level. Or you
+can 'cd tests' and then invoke individual unit tests with ./runtests.pl NNNN
+where NNNN is the specific test number.
+
+Debug Unit Tests
+================
+
+If a specific test fails you will get told. The test case then has output left
+in the log/ subdirectory, but most importantly you can re-run the test again
+using gdb by doing ./runtests.pl -g NNNN. That is, add a -g to make it start
+up gdb and run the same case using that.
+
+Write Unit Tests
+================
+
+We put tests that focus on an area or a specific function into a single C
+source file. The source file should be named 'unitNNNN.c' where NNNN is a
+number that starts with 1300 and you can pick the next free number.
+
+You also need a separate file called tests/data/testNNNN (using the same
+number) that describes your test case. See the test1300 file for inspiration
+and the tests/FILEFORMAT documentation.
+
+For the actual C file, here's a very simple example:
+
+----------------------- start -------------------------------
+#include <stdlib.h>
+#include "curl_config.h"
+#include "setup.h"
+
+#include "a libcurl header.h" /* from the lib dir */
+#include "curlcheck.h"
+
+static void unit_setup( void )
+{
+  /* whatever you want done first */
+}
+
+static void unit_stop( void )
+{
+  /* done before shutting down and exiting */
+}
+
+UNITTEST_START
+
+  /* here you start doing things and checking that the results are good */
+
+  fail_unless( size == 0 , "initial size should be zero" );
+  fail_if( head == NULL , "head should not be initiated to NULL" );
+ 
+  /* you end the test code like this: */
+ 
+UNITTEST_STOP
+
+----------------------- end -------------------------------