[PATCH net-next 4/4] selftests: drv-net: validate the environment

[Jakub Kicinski <kuba@xxxxxxxxxx>]

Throw a slightly more helpful exception when env variables
are partially populated. Prior to this change we'd get
a dictionary key exception somewhere later on.

Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
---
 .../selftests/drivers/net/lib/py/env.py       | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tools/testing/selftests/drivers/net/lib/py/env.py b/tools/testing/selftests/drivers/net/lib/py/env.py
index a6a5a5f9c6db..fda4967503de 100644
--- a/tools/testing/selftests/drivers/net/lib/py/env.py
+++ b/tools/testing/selftests/drivers/net/lib/py/env.py
@@ -88,6 +88,7 @@ from .remote import Remote
         self._ns_peer = None
 
         if "NETIF" in self.env:
+            self._check_env()
             self.dev = ip("link show dev " + self.env['NETIF'], json=True)[0]
 
             self.v4 = self.env.get("LOCAL_V4")
@@ -143,6 +144,25 @@ from .remote import Remote
         ip(f"-6 addr add dev {self._ns_peer.nsims[0].ifname} {self.nsim_v6_pfx}2/64 nodad", ns=self._netns)
         ip(f"   link set dev {self._ns_peer.nsims[0].ifname} up", ns=self._netns)
 
+    def _check_env(self):
+        vars_needed = [
+            ["LOCAL_V4", "LOCAL_V6"],
+            ["REMOTE_V4", "REMOTE_V6"],
+            ["REMOTE_TYPE"],
+            ["REMOTE_ARGS"]
+        ]
+        missing = []
+
+        for choice in vars_needed:
+            for entry in choice:
+                if entry in self.env:
+                    break
+            else:
+                missing.append(choice)
+        if missing:
+            raise Exception("Invalid environment, missing configuration:", missing,
+                            "Please see tools/testing/selftests/drivers/net/README.rst")
+
     def __enter__(self):
         return self
 
-- 
2.44.0