support/testing: add mosquitto runtime test

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 3ba6f800fdc2435d09aca215ef2e8aefb3165bff)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

DEVELOPERS

@@ -1828,6 +1828,7 @@ F:	support/testing/tests/package/test_mdadm.py
 F:	support/testing/tests/package/test_mdadm/
 F:	support/testing/tests/package/test_micropython.py
 F:	support/testing/tests/package/test_micropython/
+F:	support/testing/tests/package/test_mosquitto.py
 F:	support/testing/tests/package/test_mtools.py
 F:	support/testing/tests/package/test_mtr.py
 F:	support/testing/tests/package/test_ncdu.py

support/testing/tests/package/test_mosquitto.py

@@ -0,0 +1,38 @@
+import os
+import time
+
+import infra.basetest
+
+
+class TestMosquitto(infra.basetest.BRTest):
+    config = infra.basetest.BASIC_TOOLCHAIN_CONFIG + \
+        """
+        BR2_PACKAGE_MOSQUITTO=y
+        BR2_PACKAGE_MOSQUITTO_BROKER=y
+        BR2_TARGET_ROOTFS_CPIO=y
+        # BR2_TARGET_ROOTFS_TAR is not set
+        """
+
+    def test_run(self):
+        cpio_file = os.path.join(self.builddir, "images", "rootfs.cpio")
+        self.emulator.boot(arch="armv5",
+                           kernel="builtin",
+                           options=["-initrd", cpio_file])
+        self.emulator.login()
+
+        topic = "br-test-topic"
+        log = "mqtt.log"
+        msg = "Hello Buildroot!"
+
+        # We subscribe to a topic and write one message to a log file.
+        self.assertRunOk(f"mosquitto_sub -t {topic} -C 1 > {log} &")
+
+        time.sleep(1)
+
+        # We publish a message.
+        self.assertRunOk(f"mosquitto_pub -t {topic} -m '{msg}'")
+
+        # We check the log file contains our message.
+        out, ret = self.emulator.run(f"cat {log}")
+        self.assertEqual(ret, 0)
+        self.assertEqual(out[0], msg)