test: exclude qemu interfaces from dhcp

When running tests with a qemu managed node, the dhcp
used by qemu interferes with the dhcp used in the test, which
can cause the test to hang.  Exclude the qemu interfaces from
using the test dhcp.  Note that this only affects the qemu tests -
testing farm and other tests with "real" machines will have a
different mac address - the mac addresses used below are specific
to qemu virtual devices.

Also, just in case tests still timeout, add a tests/ansible.cfg
with a 240 second task timeout to ensure any hung tasks are killed.
This will cause the playbook to exit with an error.

Signed-off-by: Rich Megginson <[email protected]>

Author: richm

tests/ansible.cfg

@@ -0,0 +1,2 @@
+[defaults]
+task_timeout=240

tests/tasks/create_test_interfaces_with_dhcp.yml

@@ -127,11 +127,19 @@
                 fi
             done
         fi
+        # NOTE: When running tests with a qemu managed node, the dhcp
+        # used by qemu interferes with the dhcp used in the test, which
+        # can cause the test to hang.  Exclude the qemu interfaces from
+        # using the test dhcp.  Note that this only affects the qemu tests -
+        # testing farm and other tests with "real" machines will have a
+        # different mac address - the mac addresses used below are specific
+        # to qemu virtual devices.
         dnsmasq \
             --pid-file=/run/dhcp_testbr.pid \
             --dhcp-leasefile=/run/dhcp_testbr.lease \
             --dhcp-range=192.0.2.1,192.0.2.254,240 \
             --dhcp-range=2001:DB8::10,2001:DB8::1FF,slaac,64,240 \
-            --enable-ra --interface=testbr --bind-interfaces
+            --enable-ra --interface=testbr --bind-interfaces \
+            --dhcp-host 52:54:00:12:34:56,ignore --dhcp-host 52:54:00:12:34:57,ignore
     fi
   changed_when: false