[PATCH] tests/avocado: Cancel BootLinux tests in case there is no free port

[Thomas Huth <thuth@redhat.com>]

The BootLinux tests are currently failing with an ugly python
stack trace on my RHEL8 system since they cannot get a free port
(likely due to the firewall settings on my system). Let's properly
check the return value of find_free_port() instead and cancel the
test gracefully if it cannot get a free port.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 Unfortunately, it still takes > 70 seconds for each and every
 tests from tests/avocado/boot_linux.py to get canceled, so
 tests/avocado/boot_linux.py still renders "make check-avocado"
 for me pretty unusable... looking at the implementation of
 find_free_port() in Avocado, I wonder whether there isn't a
 better way to get a free port number in Python? Brute-forcing
 all ports between 1024 and 65536 seems just quite cumbersome
 to me...

 tests/avocado/avocado_qemu/__init__.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/avocado/avocado_qemu/__init__.py b/tests/avocado/avocado_qemu/__init__.py
index 75063c0c30..9b056b5ce5 100644
--- a/tests/avocado/avocado_qemu/__init__.py
+++ b/tests/avocado/avocado_qemu/__init__.py
@@ -603,6 +603,8 @@ def prepare_cloudinit(self, ssh_pubkey=None):
         try:
             cloudinit_iso = os.path.join(self.workdir, 'cloudinit.iso')
             self.phone_home_port = network.find_free_port()
+            if not self.phone_home_port:
+                self.cancel('Failed to get a free port')
             pubkey_content = None
             if ssh_pubkey:
                 with open(ssh_pubkey) as pubkey:
-- 
2.27.0