fix(v2 managed agents): add SandboxSpec validator tests

Cover idle_timeout_minutes <= timeout_minutes contract \xc2\xa76.2 invariant plus
existing timeout_minutes [1, 1440] bound. New test_types.py keeps typing
concerns separate from endpoint tests in test_agents.py.

tests/test_litellm/managed_agents/test_types.py

@@ -0,0 +1,64 @@
+"""Unit tests for ``litellm/managed_agents/types.py`` Pydantic validators.
+
+Covers contract §6.2 invariants on ``SandboxSpec``:
+- ``timeout_minutes`` ∈ [1, 1440]
+- ``idle_timeout_minutes`` ∈ [1, ``timeout_minutes``]
+"""
+
+import pytest
+from pydantic import ValidationError
+
+from litellm.managed_agents.types import SandboxSpec
+
+
+class TestSandboxSpecIdleTimeoutBound:
+    """``idle_timeout_minutes`` must not exceed ``timeout_minutes``."""
+
+    def test_idle_below_timeout_is_valid(self) -> None:
+        spec = SandboxSpec(type="opencode", timeout_minutes=60, idle_timeout_minutes=10)
+        assert spec.idle_timeout_minutes == 10
+        assert spec.timeout_minutes == 60
+
+    def test_idle_equals_timeout_is_valid(self) -> None:
+        """Boundary: idle == timeout is allowed (closed upper bound)."""
+        spec = SandboxSpec(type="opencode", timeout_minutes=60, idle_timeout_minutes=60)
+        assert spec.idle_timeout_minutes == 60
+        assert spec.timeout_minutes == 60
+
+    def test_idle_above_timeout_raises(self) -> None:
+        with pytest.raises(ValidationError) as exc_info:
+            SandboxSpec(type="opencode", timeout_minutes=60, idle_timeout_minutes=120)
+        # Surface the offending field in the error message
+        assert "idle_timeout_minutes" in str(exc_info.value)
+
+    def test_idle_and_timeout_minimum_boundary(self) -> None:
+        """Boundary: both at lower bound ``1`` is valid."""
+        spec = SandboxSpec(type="opencode", timeout_minutes=1, idle_timeout_minutes=1)
+        assert spec.idle_timeout_minutes == 1
+        assert spec.timeout_minutes == 1
+
+
+class TestSandboxSpecTimeoutBounds:
+    """``timeout_minutes`` is bounded to [1, 1440]."""
+
+    def test_timeout_above_upper_bound_raises(self) -> None:
+        with pytest.raises(ValidationError) as exc_info:
+            SandboxSpec(type="opencode", timeout_minutes=1500, idle_timeout_minutes=10)
+        assert "timeout_minutes" in str(exc_info.value)
+
+    def test_timeout_at_upper_bound_is_valid(self) -> None:
+        spec = SandboxSpec(
+            type="opencode",
+            timeout_minutes=1440,
+            idle_timeout_minutes=1440,
+        )
+        assert spec.timeout_minutes == 1440
+        assert spec.idle_timeout_minutes == 1440
+
+    def test_timeout_below_lower_bound_raises(self) -> None:
+        with pytest.raises(ValidationError):
+            SandboxSpec(type="opencode", timeout_minutes=0, idle_timeout_minutes=1)
+
+    def test_idle_timeout_below_lower_bound_raises(self) -> None:
+        with pytest.raises(ValidationError):
+            SandboxSpec(type="opencode", timeout_minutes=10, idle_timeout_minutes=0)