test: verify hostname format %h-%m in running and operational

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/case/ietf_system/hostname.py

@@ -1,13 +1,16 @@
 #!/usr/bin/env python3
 
-import random, string
-
+import random
+import string
+import re
 import infamy
 
 with infamy.Test() as test:
     with test.step("Initialize"):
         env = infamy.Env(infamy.std_topology("1x1"))
         target = env.attach("target", "mgmt")
+        tgtssh = env.attach("target", "mgmt", "ssh")
+        fmt = "%h-%m"
 
     with test.step("Set new hostname"):
         new = "".join((random.choices(string.ascii_lowercase, k=16)))
@@ -20,6 +23,30 @@ with infamy.Test() as test:
 
     with test.step(f"Verify new hostname ({new})"):
         running = target.get_config_dict("/ietf-system:system")
-        assert(running["system"]["hostname"] == new)
+        assert running["system"]["hostname"] == new
+
+    with test.step(f"Set hostname format: {fmt}"):
+        target.put_config_dict("ietf-system", {
+            "system": {
+                "hostname": fmt,
+            }
+        })
+
+    with test.step(f"Verify hostname format in running: {fmt}"):
+        running = target.get_config_dict("/ietf-system:system")
+        if running["system"]["hostname"] != fmt:
+            test.fail()
+
+        cmd = tgtssh.runsh("sed -n s/^DEFAULT_HOSTNAME=//p /etc/os-release")
+        default = cmd.stdout.rstrip()
+
+    with test.step(f"Verify hostname format in operational: {default}-c0-ff-ee"):
+
+        oper = target.get_data("/ietf-system:system")
+        name = oper["system"]["hostname"]
+        pattern = rf'^{default}-([0-9a-fA-F]{{2}}-){{2}}[0-9a-fA-F]{{2}}$'
+        regex = re.compile(pattern)
+        if not regex.match(name):
+            test.fail()
 
     test.succeed()