fix(anta.tests): BFD test module: AntaTest.Input subclasses using com…

…mon input models should have validators for their required fields. (#999)

* issue_997: BFD tests with proper validators

* improved the test coverage

* updated validator function

* addressed review commenrs: updated validator msgs

anta/tests/bfd.py

@@ -8,9 +8,9 @@
 from __future__ import annotations
 
 from datetime import datetime, timezone
-from typing import TYPE_CHECKING, ClassVar
+from typing import TYPE_CHECKING, ClassVar, TypeVar
 
-from pydantic import Field
+from pydantic import Field, field_validator
 
 from anta.input_models.bfd import BFDPeer
 from anta.models import AntaCommand, AntaTest
@@ -19,6 +19,9 @@
 if TYPE_CHECKING:
     from anta.models import AntaTemplate
 
+# Using a TypeVar for the BFDPeer model since mypy thinks it's a ClassVar and not a valid type when used in field validators
+T = TypeVar("T", bound=BFDPeer)
+
 
 class VerifyBFDSpecificPeers(AntaTest):
     """Verifies the state of IPv4 BFD peer sessions.
@@ -143,6 +146,23 @@ class Input(AntaTest.Input):
         BFDPeer: ClassVar[type[BFDPeer]] = BFDPeer
         """To maintain backward compatibility"""
 
+        @field_validator("bfd_peers")
+        @classmethod
+        def validate_bfd_peers(cls, bfd_peers: list[T]) -> list[T]:
+            """Validate that 'tx_interval', 'rx_interval' and 'multiplier' fields are provided in each BFD peer."""
+            for peer in bfd_peers:
+                missing_fileds = []
+                if peer.tx_interval is None:
+                    missing_fileds.append("tx_interval")
+                if peer.rx_interval is None:
+                    missing_fileds.append("rx_interval")
+                if peer.multiplier is None:
+                    missing_fileds.append("multiplier")
+                if missing_fileds:
+                    msg = f"{peer} {', '.join(missing_fileds)} field(s) are missing in the input."
+                    raise ValueError(msg)
+            return bfd_peers
+
     @AntaTest.anta_test
     def test(self) -> None:
         """Main test function for VerifyBFDPeersIntervals."""
@@ -308,6 +328,16 @@ class Input(AntaTest.Input):
         BFDPeer: ClassVar[type[BFDPeer]] = BFDPeer
         """To maintain backward compatibility"""
 
+        @field_validator("bfd_peers")
+        @classmethod
+        def validate_bfd_peers(cls, bfd_peers: list[T]) -> list[T]:
+            """Validate that 'protocols' field is provided in each BFD peer."""
+            for peer in bfd_peers:
+                if peer.protocols is None:
+                    msg = f"{peer} 'protocols' field missing in the input."
+                    raise ValueError(msg)
+            return bfd_peers
+
     @AntaTest.anta_test
     def test(self) -> None:
         """Main test function for VerifyBFDPeersRegProtocols."""

tests/units/input_models/test_bfd.py

@@ -0,0 +1,68 @@
+# Copyright (c) 2023-2025 Arista Networks, Inc.
+# Use of this source code is governed by the Apache License 2.0
+# that can be found in the LICENSE file.
+"""Tests for anta.input_models.bfd.py."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import pytest
+from pydantic import ValidationError
+
+from anta.tests.bfd import VerifyBFDPeersIntervals, VerifyBFDPeersRegProtocols
+
+if TYPE_CHECKING:
+    from anta.input_models.bfd import BFDPeer
+
+
+class TestVerifyBFDPeersIntervalsInput:
+    """Test anta.tests.bfd.VerifyBFDPeersIntervals.Input."""
+
+    @pytest.mark.parametrize(
+        ("bfd_peers"),
+        [
+            pytest.param([{"peer_address": "10.0.0.1", "vrf": "default", "tx_interval": 1200, "rx_interval": 1200, "multiplier": 3}], id="valid"),
+        ],
+    )
+    def test_valid(self, bfd_peers: list[BFDPeer]) -> None:
+        """Test VerifyBFDPeersIntervals.Input valid inputs."""
+        VerifyBFDPeersIntervals.Input(bfd_peers=bfd_peers)
+
+    @pytest.mark.parametrize(
+        ("bfd_peers"),
+        [
+            pytest.param([{"peer_address": "10.0.0.1", "vrf": "default", "tx_interval": 1200}], id="invalid-tx-interval"),
+            pytest.param([{"peer_address": "10.0.0.1", "vrf": "default", "rx_interval": 1200}], id="invalid-rx-interval"),
+            pytest.param([{"peer_address": "10.0.0.1", "vrf": "default", "tx_interval": 1200, "rx_interval": 1200}], id="invalid-multiplier"),
+        ],
+    )
+    def test_invalid(self, bfd_peers: list[BFDPeer]) -> None:
+        """Test VerifyBFDPeersIntervals.Input invalid inputs."""
+        with pytest.raises(ValidationError):
+            VerifyBFDPeersIntervals.Input(bfd_peers=bfd_peers)
+
+
+class TestVerifyBFDPeersRegProtocolsInput:
+    """Test anta.tests.bfd.VerifyBFDPeersRegProtocols.Input."""
+
+    @pytest.mark.parametrize(
+        ("bfd_peers"),
+        [
+            pytest.param([{"peer_address": "10.0.0.1", "vrf": "default", "protocols": ["bgp"]}], id="valid"),
+        ],
+    )
+    def test_valid(self, bfd_peers: list[BFDPeer]) -> None:
+        """Test VerifyBFDPeersRegProtocols.Input valid inputs."""
+        VerifyBFDPeersRegProtocols.Input(bfd_peers=bfd_peers)
+
+    @pytest.mark.parametrize(
+        ("bfd_peers"),
+        [
+            pytest.param([{"peer_address": "10.0.0.1", "vrf": "default"}], id="invalid"),
+        ],
+    )
+    def test_invalid(self, bfd_peers: list[BFDPeer]) -> None:
+        """Test VerifyBFDPeersRegProtocols.Input invalid inputs."""
+        with pytest.raises(ValidationError):
+            VerifyBFDPeersRegProtocols.Input(bfd_peers=bfd_peers)