test-tester: This add tests for tester

This adds tests for the tester itself:

> unit/test-tester

Test Summary
------------
/tester/basic                           Passed       0.000 seconds
/tester/setup_io                        Passed       0.000 seconds
/tester/io_send                         Passed       0.000 seconds
Total: 3, Passed: 3 (100.0%), Failed: 0, Not Run: 0
Overall execution time: 0.000355 seconds

1 files changed, 92 insertions, 0 deletions

diff --git a/unit/test-tester.c b/unit/test-tester.c
new file mode 100644
index 000000000..7cdfc87b8
--- /dev/null
+++ b/unit/test-tester.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ *  BlueZ - Bluetooth protocol stack for Linux
+ *
+ *  Copyright (C) 2022  Intel Corporation.
+ *
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <fcntl.h>
+
+#include <glib.h>
+
+#include "src/shared/util.h"
+#include "src/shared/tester.h"
+
+static void test_basic(const void *data)
+{
+	tester_test_passed();
+}
+
+static bool test_io_recv(struct io *io, void *user_data)
+{
+	const struct iovec *iov = user_data;
+	unsigned char buf[512];
+	int fd;
+	ssize_t len;
+
+	fd = io_get_fd(io);
+
+	len = read(fd, buf, sizeof(buf));
+
+	g_assert(len > 0);
+	g_assert_cmpint(len, ==, iov->iov_len);
+	g_assert(memcmp(buf, iov->iov_base, len) == 0);
+
+	tester_test_passed();
+
+	return false;
+}
+
+static const struct iovec iov[] = {
+	IOV_DATA(0x01),
+	IOV_DATA(0x01, 0x02),
+};
+
+static void test_setup_io(const void *data)
+{
+	struct io *io;
+	ssize_t len;
+
+	io = tester_setup_io(iov, ARRAY_SIZE(iov));
+	g_assert(io);
+
+	io_set_read_handler(io, test_io_recv, (void *)&iov[1], NULL);
+
+	len = io_send(io, (void *)&iov[0], 1);
+	g_assert_cmpint(len, ==, iov[0].iov_len);
+}
+
+static void test_io_send(const void *data)
+{
+	struct io *io;
+
+	io = tester_setup_io(iov, ARRAY_SIZE(iov));
+	g_assert(io);
+
+	io_set_read_handler(io, test_io_recv, (void *)&iov[0], NULL);
+
+	tester_io_send();
+}
+
+int main(int argc, char *argv[])
+{
+	tester_init(&argc, &argv);
+
+	tester_add("/tester/basic", NULL, NULL, test_basic, NULL);
+	tester_add("/tester/setup_io", NULL, NULL, test_setup_io, NULL);
+	tester_add("/tester/io_send", NULL, NULL, test_io_send, NULL);
+
+	return tester_run();
+}
+