fix: harden PR body validator for mixed escaped-newline and tea path (#392)

tests/test_validate_pr_body.py

@@ -24,9 +24,24 @@ def test_validate_pr_body_text_detects_escaped_newline() -> None:
     assert any("escaped newline" in err for err in errors)
 
 
-def test_validate_pr_body_text_allows_literal_sequence_when_multiline() -> None:
+def test_validate_pr_body_text_detects_escaped_newline_in_multiline_body() -> None:
     module = _load_module()
-    text = "## Summary\n- escaped sequence example: \\\\n"
+    text = "## Summary\n- first line\n- broken line with \\n literal"
+    errors = module.validate_pr_body_text(text)
+    assert any("escaped newline" in err for err in errors)
+
+
+def test_validate_pr_body_text_allows_escaped_newline_in_code_blocks() -> None:
+    module = _load_module()
+    text = "\n".join(
+        [
+            "## Summary",
+            "- example uses `\\n` for explanation",
+            "```bash",
+            "printf 'line1\\nline2\\n'",
+            "```",
+        ]
+    )
     assert module.validate_pr_body_text(text) == []
 
 
@@ -63,12 +78,13 @@ def test_fetch_pr_body_reads_body_from_tea_api(monkeypatch) -> None:
     module = _load_module()
 
     def fake_run(cmd, check, capture_output, text):  # noqa: ANN001
-        assert "tea" in cmd[0]
+        assert cmd[0] == "/tmp/tea-bin"
         assert check is True
         assert capture_output is True
         assert text is True
         return SimpleNamespace(stdout=json.dumps({"body": "## Summary\n- item"}))
 
+    monkeypatch.setattr(module, "resolve_tea_binary", lambda: "/tmp/tea-bin")
     monkeypatch.setattr(module.subprocess, "run", fake_run)
     assert module.fetch_pr_body(391) == "## Summary\n- item"
 
@@ -79,6 +95,18 @@ def test_fetch_pr_body_rejects_non_string_body(monkeypatch) -> None:
     def fake_run(cmd, check, capture_output, text):  # noqa: ANN001
         return SimpleNamespace(stdout=json.dumps({"body": 123}))
 
+    monkeypatch.setattr(module, "resolve_tea_binary", lambda: "/tmp/tea-bin")
     monkeypatch.setattr(module.subprocess, "run", fake_run)
     with pytest.raises(RuntimeError):
         module.fetch_pr_body(391)
+
+
+def test_resolve_tea_binary_falls_back_to_home_bin(monkeypatch, tmp_path) -> None:
+    module = _load_module()
+    tea_home = tmp_path / "bin" / "tea"
+    tea_home.parent.mkdir(parents=True)
+    tea_home.write_text("#!/usr/bin/env bash\n", encoding="utf-8")
+
+    monkeypatch.setattr(module.shutil, "which", lambda _: None)
+    monkeypatch.setattr(module.Path, "home", lambda: tmp_path)
+    assert module.resolve_tea_binary() == str(tea_home)