process: add mandatory PR body post-check step (#392)

tests/test_validate_pr_body.py

@@ -0,0 +1,84 @@
+from __future__ import annotations
+
+import importlib.util
+import json
+from pathlib import Path
+from types import SimpleNamespace
+
+import pytest
+
+
+def _load_module():
+    script_path = Path(__file__).resolve().parents[1] / "scripts" / "validate_pr_body.py"
+    spec = importlib.util.spec_from_file_location("validate_pr_body", script_path)
+    assert spec is not None
+    assert spec.loader is not None
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_validate_pr_body_text_detects_escaped_newline() -> None:
+    module = _load_module()
+    errors = module.validate_pr_body_text("## Summary\\n- item")
+    assert any("escaped newline" in err for err in errors)
+
+
+def test_validate_pr_body_text_allows_literal_sequence_when_multiline() -> None:
+    module = _load_module()
+    text = "## Summary\n- escaped sequence example: \\\\n"
+    assert module.validate_pr_body_text(text) == []
+
+
+def test_validate_pr_body_text_detects_unbalanced_code_fence() -> None:
+    module = _load_module()
+    errors = module.validate_pr_body_text("## Summary\n- item\n```bash\necho hi\n")
+    assert any("unbalanced fenced code blocks" in err for err in errors)
+
+
+def test_validate_pr_body_text_detects_missing_structure() -> None:
+    module = _load_module()
+    errors = module.validate_pr_body_text("plain text only")
+    assert any("missing markdown section headers" in err for err in errors)
+    assert any("missing markdown list items" in err for err in errors)
+
+
+def test_validate_pr_body_text_passes_with_valid_markdown() -> None:
+    module = _load_module()
+    text = "\n".join(
+        [
+            "## Summary",
+            "- item",
+            "",
+            "## Validation",
+            "```bash",
+            "pytest -q",
+            "```",
+        ]
+    )
+    assert module.validate_pr_body_text(text) == []
+
+
+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 check is True
+        assert capture_output is True
+        assert text is True
+        return SimpleNamespace(stdout=json.dumps({"body": "## Summary\n- item"}))
+
+    monkeypatch.setattr(module.subprocess, "run", fake_run)
+    assert module.fetch_pr_body(391) == "## Summary\n- item"
+
+
+def test_fetch_pr_body_rejects_non_string_body(monkeypatch) -> None:
+    module = _load_module()
+
+    def fake_run(cmd, check, capture_output, text):  # noqa: ANN001
+        return SimpleNamespace(stdout=json.dumps({"body": 123}))
+
+    monkeypatch.setattr(module.subprocess, "run", fake_run)
+    with pytest.raises(RuntimeError):
+        module.fetch_pr_body(391)