--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-log.c	Sun Jan 10 18:10:52 2021 +0100
@@ -0,0 +1,164 @@
+/*
+ * test-log.c -- test log.h functions
+ *
+ * Copyright (c) 2013-2021 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#define GREATEST_USE_ABBREVS 0
+#include <greatest.h>
+
+#include <irccd/log.h>
+
+/*
+ * Note: we can't really test logs to console and syslog, so use files as best effort. Write some
+ * data and check that it is correctly written.
+ */
+
+static void
+clean(void *udata)
+{
+	(void)udata;
+
+	remove("stdout.txt");
+	remove("stderr.txt");
+}
+
+GREATEST_TEST
+basics_info_verbose_off(void)
+{
+	FILE *fpout, *fperr;
+	char out[128] = {0}, err[128] = {0};
+
+	/* Default is quiet, should not log. */
+	irc_log_to_files("stdout.txt", "stderr.txt");
+	irc_log_info("hello world!");
+
+	if (!(fpout = fopen("stdout.txt", "r")) || !(fperr = fopen("stderr.txt", "r")))
+		GREATEST_FAIL();
+
+	fgets(out, sizeof (out), fpout);
+	fgets(err, sizeof (err), fperr);
+
+	GREATEST_ASSERT_STR_EQ("", out);
+	GREATEST_ASSERT_STR_EQ("", err);
+
+	GREATEST_PASS();
+}
+
+GREATEST_TEST
+basics_info_verbose_on(void)
+{
+	FILE *fpout, *fperr;
+	char out[128] = {0}, err[128] = {0};
+
+	irc_log_set_verbose(true);
+	irc_log_to_files("stdout.txt", "stderr.txt");
+	irc_log_info("hello world!");
+	irc_log_info("what's up?");
+
+	if (!(fpout = fopen("stdout.txt", "r")) || !(fperr = fopen("stderr.txt", "r")))
+		GREATEST_FAIL();
+
+	GREATEST_ASSERT(fgets(out, sizeof (out), fpout));
+	GREATEST_ASSERT_STR_EQ("hello world!\n", out);
+	GREATEST_ASSERT(fgets(out, sizeof (out), fpout));
+	GREATEST_ASSERT_STR_EQ("what's up?\n", out);
+
+	GREATEST_ASSERT(!fgets(err, sizeof (err), fperr));
+	GREATEST_ASSERT_STR_EQ("", err);
+	GREATEST_ASSERT(!fgets(err, sizeof (err), fperr));
+	GREATEST_ASSERT_STR_EQ("", err);
+
+	GREATEST_PASS();
+}
+
+GREATEST_TEST
+basics_warn(void)
+{
+	FILE *fpout, *fperr;
+	char out[128] = {0}, err[128] = {0};
+
+	/* Warning messages are printed even without verbosity. */
+	irc_log_set_verbose(false);
+	irc_log_to_files("stdout.txt", "stderr.txt");
+	irc_log_warn("error line 1");
+	irc_log_warn("error line 2");
+
+	if (!(fpout = fopen("stdout.txt", "r")) || !(fperr = fopen("stderr.txt", "r")))
+		GREATEST_FAIL();
+
+	GREATEST_ASSERT(!fgets(out, sizeof (out), fpout));
+	GREATEST_ASSERT_STR_EQ("", out);
+	GREATEST_ASSERT(!fgets(out, sizeof (out), fpout));
+	GREATEST_ASSERT_STR_EQ("", out);
+
+	GREATEST_ASSERT(fgets(err, sizeof (err), fperr));
+	GREATEST_ASSERT_STR_EQ("error line 1\n", err);
+	GREATEST_ASSERT(fgets(err, sizeof (err), fperr));
+	GREATEST_ASSERT_STR_EQ("error line 2\n", err);
+
+	GREATEST_PASS();
+}
+
+GREATEST_TEST
+basics_debug(void)
+{
+#if !defined(NDEBUG)
+	FILE *fpout, *fperr;
+	char out[128] = {0}, err[128] = {0};
+
+	/* Debug messages are printed even without verbosity but requires to be built in debug. */
+	irc_log_set_verbose(false);
+	irc_log_to_files("stdout.txt", "stderr.txt");
+	irc_log_debug("startup!");
+	irc_log_debug("shutdown!");
+
+	if (!(fpout = fopen("stdout.txt", "r")) || !(fperr = fopen("stderr.txt", "r")))
+		GREATEST_FAIL();
+
+	GREATEST_ASSERT(fgets(out, sizeof (out), fpout));
+	GREATEST_ASSERT_STR_EQ("startup!\n", out);
+	GREATEST_ASSERT(fgets(out, sizeof (out), fpout));
+	GREATEST_ASSERT_STR_EQ("shutdown!\n", out);
+
+	GREATEST_ASSERT(!fgets(err, sizeof (err), fperr));
+	GREATEST_ASSERT_STR_EQ("", err);
+	GREATEST_ASSERT(!fgets(err, sizeof (err), fperr));
+	GREATEST_ASSERT_STR_EQ("", err);
+#endif
+	GREATEST_PASS();
+}
+
+GREATEST_SUITE(suite_basics)
+{
+	GREATEST_SET_SETUP_CB(clean, NULL);
+	GREATEST_SET_TEARDOWN_CB(clean, NULL);
+	GREATEST_RUN_TEST(basics_info_verbose_off);
+	GREATEST_RUN_TEST(basics_info_verbose_on);
+	GREATEST_RUN_TEST(basics_warn);
+	GREATEST_RUN_TEST(basics_debug);
+}
+
+GREATEST_MAIN_DEFS();
+
+int
+main(int argc, char **argv)
+{
+	GREATEST_MAIN_BEGIN();
+	GREATEST_RUN_SUITE(suite_basics);
+	GREATEST_MAIN_END();
+
+	return 0;
+}