test: cover declined, timed out, cancelled and absent prompts

The four kinds and the words each produces, at the registry level and through
the four policy gates: a timeout names its deadline, a decline carries the
comment, and neither is reported as the other. The existing denial assertions
now expect the specific clause.

tests/test_agent/test_tool_denial.py

@@ -0,0 +1,71 @@
+"""A denial says which no it was: the human's, the clock's, or nobody's."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from plyngent.agent import Denial, DenialKind, ToolRegistry, tool
+
+if TYPE_CHECKING:
+    from collections.abc import Mapping
+
+
+def _danger(name: str, _args: Mapping[str, object]) -> str | None:
+    return f"mutate {name}"
+
+
+@tool(register=False)
+async def mutate() -> str:
+    return "ran"
+
+
+def _registry(answer: object) -> ToolRegistry:
+    """A registry whose one soft confirm answers *answer*."""
+    return ToolRegistry([mutate], danger=_danger, on_confirm=lambda *_args: answer)
+
+
+async def test_a_declined_prompt_says_the_user_declined() -> None:
+    out = await _registry(Denial(DenialKind.DECLINED)).execute("mutate", "{}")
+    assert out.startswith("error: tool 'mutate' denied (")
+    assert "user declined" in out
+    assert "no answer" not in out
+
+
+async def test_a_timeout_names_its_deadline_instead_of_the_user() -> None:
+    out = await _registry(Denial(DenialKind.TIMEOUT, seconds=30.0)).execute("mutate", "{}")
+    assert "no answer within 30s — denied by default" in out
+    assert "user declined" not in out
+
+
+async def test_a_cancelled_prompt_says_so() -> None:
+    out = await _registry(Denial(DenialKind.CANCELLED)).execute("mutate", "{}")
+    assert "prompt cancelled" in out
+
+
+async def test_no_prompt_says_nobody_was_asked() -> None:
+    out = await _registry(Denial(DenialKind.NO_PROMPT)).execute("mutate", "{}")
+    assert "no confirm hook or non-interactive" in out
+
+
+async def test_a_bare_comment_still_reads_as_a_declined_human() -> None:
+    out = await _registry("my tax data").execute("mutate", "{}")
+    assert "user declined" in out
+    assert "user comment: my tax data" in out
+
+
+def test_a_timeout_without_a_deadline_still_says_default_deny() -> None:
+    assert Denial(DenialKind.TIMEOUT).clause() == "no answer — denied by default"
+
+
+def test_the_denial_clause_never_claims_a_human() -> None:
+    """A timeout must not be reported as a decision, nor an absent prompt as one."""
+    assert "user" not in Denial(DenialKind.TIMEOUT, seconds=5.0).clause()
+    assert "user" not in Denial(DenialKind.NO_PROMPT).clause()
+
+
+def test_from_answer_keeps_a_denial_and_reads_a_comment() -> None:
+    timeout = Denial(DenialKind.TIMEOUT, seconds=1.0)
+    assert Denial.from_answer(timeout) is timeout
+    assert Denial.from_answer("why not") == Denial(comment="why not")
+    assert Denial.from_answer(None) == Denial(DenialKind.DECLINED)
+    assert Denial.from_answer(False) == Denial(DenialKind.DECLINED)