support/testing: add tcpdump runtime test

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

DEVELOPERS

@@ -1822,6 +1822,7 @@ F:	support/testing/tests/package/test_strace.py
 F:	support/testing/tests/package/test_stress_ng.py
 F:	support/testing/tests/package/test_tcl.py
 F:	support/testing/tests/package/test_tcl/
+F:	support/testing/tests/package/test_tcpdump.py
 F:	support/testing/tests/package/test_weston.py
 F:	support/testing/tests/package/test_weston/
 F:	support/testing/tests/package/test_xz.py

support/testing/tests/package/test_tcpdump.py

@@ -0,0 +1,46 @@
+import os
+import time
+
+import infra.basetest
+
+
+class TestTcpdump(infra.basetest.BRTest):
+    config = infra.basetest.BASIC_TOOLCHAIN_CONFIG + \
+        """
+        BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y
+        BR2_PACKAGE_TCPDUMP=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()
+
+        capture_file = "capture.pcap"
+        decode_log = "decode.log"
+
+        # Check the program can execute.
+        self.assertRunOk("tcpdump --version")
+
+        # Run ping in background.
+        cmd = "ping localhost >/dev/null &"
+        self.assertRunOk(cmd)
+
+        time.sleep(1)
+
+        # Capture 3 packets with the message.
+        cmd = f"tcpdump -c 3 -w {capture_file} icmp"
+        self.assertRunOk(cmd)
+
+        # Decode the capture file.
+        cmd = f"tcpdump -r {capture_file} > {decode_log}"
+        self.assertRunOk(cmd)
+
+        # Check we have ICMP echo requests/replies in the
+        # decoded capture.
+        cmd = f"grep -E 'ICMP echo (request|reply)' {decode_log}"
+        self.assertRunOk(cmd)