support/testing: add socat runtime test

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit b1bbc7ac6ea90baef7559fc33d2a7e067428eebc)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

DEVELOPERS

@@ -1853,6 +1853,7 @@ F:	support/testing/tests/package/test_rdma_core.py
 F:	support/testing/tests/package/test_rdma_core/
 F:	support/testing/tests/package/test_screen.py
 F:	support/testing/tests/package/test_sed.py
+F:	support/testing/tests/package/test_socat.py
 F:	support/testing/tests/package/test_sox.py
 F:	support/testing/tests/package/test_sqlite.py
 F:	support/testing/tests/package/test_strace.py

support/testing/tests/package/test_socat.py

@@ -0,0 +1,56 @@
+import os
+import time
+
+import infra.basetest
+
+
+class TestSoCat(infra.basetest.BRTest):
+    config = infra.basetest.BASIC_TOOLCHAIN_CONFIG + \
+        """
+        BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y
+        BR2_PACKAGE_NETCAT=y
+        BR2_PACKAGE_SOCAT=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()
+
+        # Some values, for the test.
+        msg = "Hello Buildroot!"
+        out_file = "output.txt"
+        port1 = 11111
+        port2 = 22222
+
+        # Check the program can execute.
+        self.assertRunOk("socat -V")
+
+        # We start the receiver netcat on tcp/port2.
+        cmd = f"nc -n -l -p {port2} > {out_file} 2> /dev/null &"
+        self.assertRunOk(cmd)
+
+        time.sleep(2 * self.timeout_multiplier)
+
+        # We start socat in background to listen on tcp/port1 and
+        # forward to tcp/port2.
+        cmd = f"socat TCP4-LISTEN:{port1} TCP4:127.0.0.1:{port2} &"
+        self.assertRunOk(cmd)
+
+        time.sleep(2 * self.timeout_multiplier)
+
+        # We write a message on tcp/port1. Socat is expected to
+        # forward the message to the receiver on tcp/port2, and write
+        # our message in a file.
+        cmd = f"echo '{msg}' | nc -n -c 127.0.0.1 {port1}"
+        self.assertRunOk(cmd)
+
+        # We check the output file contains our message.
+        cmd = f"cat {out_file}"
+        out, ret = self.emulator.run(cmd)
+        self.assertEqual(ret, 0)
+        self.assertEqual(out[0], msg)