Add unit testing support via cmocka

cmocka [1,2] is a testing framework for C. Adding unit test
capabilities to the openvpn repository will greatly ease the
task of writing correct code.

cmocka source code is added as git submodule in ./vendor. A
submodule approach has been chosen over a classical library
dependency because libcmocka is not available, or only
available in very old versions (e.g. on Ubuntu).

cmocka is build during 'make check' and installed in vendor/dist/.

[1] https://cmocka.org/
[2] https://lwn.net/Articles/558106/

Signed-off-by: Jens Neuhalfen <jens@neuhalfen.name>
Acked-by: Steffan Karger <steffan@karger.me>
Message-Id: <20160525175756.56186-2-openvpn-devel@neuhalfen.name>
URL: http://article.gmane.org/gmane.network.openvpn.devel/11725
Signed-off-by: David Sommerseth <dazo@privateinternetaccess.com>
(cherry picked from commit 40cb4cfc5d011102daec61ab39583cba0eeb3077)

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "vendor/cmocka"]
+	path = vendor/cmocka
+	url = git://git.cryptomilk.org/projects/cmocka.git
+	branch = master

Makefile.am

@@ -54,7 +54,7 @@ BUILT_SOURCES = \
 	config-version.h
 endif
 
-SUBDIRS = build distro include src sample doc tests
+SUBDIRS = build distro include src sample doc vendor tests
 
 dist_doc_DATA = \
 	README \

configure.ac

@@ -1119,6 +1119,19 @@ sampledir="\$(docdir)/sample"
 AC_SUBST([plugindir])
 AC_SUBST([sampledir])
 
+VENDOR_SRC_ROOT="\$(abs_top_srcdir)/vendor/"
+VENDOR_DIST_ROOT="\$(abs_top_builddir)/vendor/dist"
+VENDOR_BUILD_ROOT="\$(abs_top_builddir)/vendor/.build"
+AC_SUBST([VENDOR_SRC_ROOT])
+AC_SUBST([VENDOR_BUILD_ROOT])
+AC_SUBST([VENDOR_DIST_ROOT])
+
+TEST_LDFLAGS="-lcmocka -L\$(abs_top_builddir)/vendor/dist/lib -Wl,-rpath,\$(abs_top_builddir)/vendor/dist/lib"
+TEST_CFLAGS="-I\$(top_srcdir)/include -I\$(abs_top_builddir)/vendor/dist/include"
+
+AC_SUBST([TEST_LDFLAGS])
+AC_SUBST([TEST_CFLAGS])
+
 AC_CONFIG_FILES([
 	version.sh
 	Makefile
@@ -1137,6 +1150,9 @@ AC_CONFIG_FILES([
 	src/plugins/auth-pam/Makefile
 	src/plugins/down-root/Makefile
 	tests/Makefile
+        tests/unit_tests/Makefile
+        tests/unit_tests/example_test/Makefile
+        vendor/Makefile
 	sample/Makefile
 	doc/Makefile
 ])

tests/Makefile.am

@@ -12,6 +12,8 @@
 MAINTAINERCLEANFILES = \
 	$(srcdir)/Makefile.in
 
+SUBDIRS = unit_tests
+
 test_scripts = t_client.sh t_lpback.sh t_cltsrv.sh
 
 TESTS_ENVIRONMENT = top_srcdir="$(top_srcdir)"
@@ -20,4 +22,3 @@ TESTS = $(test_scripts)
 dist_noinst_SCRIPTS = \
 	$(test_scripts) \
 	t_cltsrv-down.sh
-

tests/unit_tests/.gitignore

@@ -0,0 +1 @@
+*_testdriver

tests/unit_tests/Makefile.am

@@ -0,0 +1,3 @@
+AUTOMAKE_OPTIONS = foreign
+
+SUBDIRS = example_test

tests/unit_tests/README.md

@@ -0,0 +1,40 @@
+Unit Tests
+===========
+
+This directory contains unit tests for openvpn. New features/bugfixes should be written in a test friendly way and come with corresponding tests.
+
+Run tests
+----------
+
+Tests are run by `make check`. A failed tests stops test execution. To run all
+tests regardless of errors call `make -k check`.
+
+Add new tests to existing test suite
+-------------------------------------
+
+Test suites are organized in directories. [example_test/](example_test/) is an example
+for a test suite with two test executables. Feel free to use it as a template for new tests.
+
+Test suites
+--------------------
+
+Test suites live inside a subdirectory of `$ROOT/tests/unit_tests`, e.g. `$ROOT/tests/unit_tests/my_feature`.
+
+Test suites are configured by a `Makefile.am`. Tests are executed by testdrivers. One testsuite can contain more than one testdriver.
+
+### Hints
+* Name suites & testdrivers in a way that the name of the driver says something about which component/feature is tested
+* Name the testdriver executable `*_testdriver`. This way it gets picked up by the default `.gitignore`
+  * If this is not feasible: Add all output to a `.gitignore`* Use descriptive test names: `coffee_brewing__with_no_beans__fails` vs. `test34`
+* Testing a configurable feature?  Wrap test execution with a conditional (see [auth_pam](plugins/auth-pam/Makefile.am) for an example)
+* Add multiple test-drivers when one testdriver looks crowded with tests
+
+### New Test Suites
+1.  Organize tests in folders for features.
+2.  Add the new test directory to `SUBDIRS` in `Makefile.am`
+3.  Edit `configure.ac` and add the new `Makefile` to `AC_CONFIG_FILES`
+4.  Run `./configure`, and *enable* the feature you'd like to test
+5.  Make sure that `make check` runs your tests
+6.  Check: Would a stranger be able to easily find your tests by you looking at the test output?
+7. Run `./configure`, and *disable* the feature you'd like to test
+8.  Make sure that `make check` does *not run* your tests

tests/unit_tests/example_test/Makefile.am

@@ -0,0 +1,13 @@
+AUTOMAKE_OPTIONS = foreign
+
+check_PROGRAMS = example_testdriver example2_testdriver
+
+TESTS = $(check_PROGRAMS)
+
+example_testdriver_CFLAGS  = @TEST_CFLAGS@
+example_testdriver_LDFLAGS = @TEST_LDFLAGS@
+example_testdriver_SOURCES = test.c
+
+example2_testdriver_CFLAGS  = @TEST_CFLAGS@
+example2_testdriver_LDFLAGS = @TEST_LDFLAGS@
+example2_testdriver_SOURCES = test2.c

tests/unit_tests/example_test/README.md

@@ -0,0 +1,3 @@
+This test only checks that test compilation works. This example contains two test executables.
+
+These tests can be used as template for 'real' tests.

tests/unit_tests/example_test/test.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+static int setup(void **state) {
+     int *answer  = malloc(sizeof(int));
+
+     *answer=42;
+     *state=answer;
+
+     return 0;
+}
+
+static int teardown(void **state) {
+     free(*state);
+
+     return 0;
+}
+
+static void null_test_success(void **state) {
+    (void) state;
+}
+
+static void int_test_success(void **state) {
+     int *answer = *state;
+     assert_int_equal(*answer, 42);
+}
+
+static void failing_test(void **state) {
+     // This tests fails to test that make check fails
+     assert_int_equal(0, 42);
+}
+
+int main(void) {
+    const struct CMUnitTest tests[] = {
+        cmocka_unit_test(null_test_success),
+        cmocka_unit_test_setup_teardown(int_test_success, setup, teardown),
+//        cmocka_unit_test(failing_test),
+    };
+
+    return cmocka_run_group_tests_name("success_test", tests, NULL, NULL);
+}

tests/unit_tests/example_test/test2.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+
+static void test_true(void **state) {
+    (void) state;
+}
+
+
+int main(void) {
+    const struct CMUnitTest tests[] = {
+        cmocka_unit_test(test_true),
+    };
+
+    return cmocka_run_group_tests_name("success_test2", tests, NULL, NULL);
+}

vendor/.gitignore

@@ -0,0 +1,2 @@
+.build/
+dist/

vendor/Makefile.am

@@ -0,0 +1,24 @@
+AUTOMAKE_OPTIONS = foreign
+
+cmockasrc     = @VENDOR_SRC_ROOT@/cmocka  # needs an absolute path bc. of the cmake invocation
+cmockabuild   = @VENDOR_BUILD_ROOT@/cmocka
+cmockainstall = @VENDOR_DIST_ROOT@
+
+MAINTAINERCLEANFILES = \
+	$(srcdir)/Makefile.in \
+	$(cmockabuild) \
+	$(cmockainstall) \
+	@VENDOR_BUILD_ROOT@
+
+distdir:
+	mkdir -p $(cmockainstall)
+
+libcmocka: distdir
+	mkdir -p $(cmockabuild)
+	(cd $(cmockabuild) && cmake -DCMAKE_INSTALL_PREFIX=$(cmockainstall) $(cmockasrc) && make && make install)
+
+check: libcmocka
+
+clean:
+	rm -rf $(cmockabuild)
+	rm -rf $(cmockainstall)

vendor/README.md

@@ -0,0 +1,8 @@
+Vendor
+========
+
+Vendor source libraries are included in this directory. Libraries are included
+when there is no good way to ensure that the package is available on all
+systems.
+
+`Makefile.am` compiles these libraries and installs them into ./dist.

vendor/cmocka

@@ -0,0 +1 @@
+Subproject commit b2732b52202ae48f866a024c633466efdbb8e85a