feat: Implement diff-scope functionality for pull requests and CI integration

tests/interface/test_diff_scope.py

@@ -0,0 +1,98 @@
+import importlib.util
+from pathlib import Path
+
+
+def _load_utils_module():
+    module_path = Path(__file__).resolve().parents[2] / "strix" / "interface" / "utils.py"
+    spec = importlib.util.spec_from_file_location("strix_interface_utils_test", module_path)
+    if spec is None or spec.loader is None:
+        raise RuntimeError("Failed to load strix.interface.utils for tests")
+
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+utils = _load_utils_module()
+
+
+def test_parse_name_status_uses_rename_destination_path() -> None:
+    raw = (
+        b"R100\x00old/path.py\x00new/path.py\x00"
+        b"R75\x00legacy/module.py\x00modern/module.py\x00"
+        b"M\x00src/app.py\x00"
+        b"A\x00src/new_file.py\x00"
+        b"D\x00src/deleted.py\x00"
+    )
+
+    entries = utils._parse_name_status_z(raw)
+    classified = utils._classify_diff_entries(entries)
+
+    assert "new/path.py" in classified["analyzable_files"]
+    assert "old/path.py" not in classified["analyzable_files"]
+    assert "modern/module.py" in classified["analyzable_files"]
+    assert classified["renamed_files"][0]["old_path"] == "old/path.py"
+    assert classified["renamed_files"][0]["new_path"] == "new/path.py"
+    assert "src/deleted.py" in classified["deleted_files"]
+    assert "src/deleted.py" not in classified["analyzable_files"]
+
+
+def test_build_diff_scope_instruction_includes_added_modified_and_deleted_guidance() -> None:
+    scope = utils.RepoDiffScope(
+        source_path="/tmp/repo",
+        workspace_subdir="repo",
+        base_ref="refs/remotes/origin/main",
+        merge_base="abc123",
+        added_files=["src/added.py"],
+        modified_files=["src/changed.py"],
+        renamed_files=[{"old_path": "src/old.py", "new_path": "src/new.py", "similarity": 90}],
+        deleted_files=["src/deleted.py"],
+        analyzable_files=["src/added.py", "src/changed.py", "src/new.py"],
+    )
+
+    instruction = utils.build_diff_scope_instruction([scope])
+
+    assert "For Added files, review the entire file content." in instruction
+    assert "For Modified files, focus primarily on the changed areas." in instruction
+    assert "Note: These files were deleted" in instruction
+    assert "src/deleted.py" in instruction
+    assert "src/old.py -> src/new.py" in instruction
+
+
+def test_resolve_base_ref_prefers_github_base_ref(monkeypatch) -> None:
+    calls: list[str] = []
+
+    def fake_ref_exists(_repo_path: Path, ref: str) -> bool:
+        calls.append(ref)
+        return ref == "refs/remotes/origin/release-2026"
+
+    monkeypatch.setattr(utils, "_git_ref_exists", fake_ref_exists)
+    monkeypatch.setattr(utils, "_extract_github_base_sha", lambda _env: None)
+    monkeypatch.setattr(utils, "_resolve_origin_head_ref", lambda _repo_path: None)
+
+    base_ref = utils._resolve_base_ref(
+        Path("/tmp/repo"),
+        diff_base=None,
+        env={"GITHUB_BASE_REF": "release-2026"},
+    )
+
+    assert base_ref == "refs/remotes/origin/release-2026"
+    assert calls[0] == "refs/remotes/origin/release-2026"
+
+
+def test_resolve_base_ref_falls_back_to_remote_main(monkeypatch) -> None:
+    calls: list[str] = []
+
+    def fake_ref_exists(_repo_path: Path, ref: str) -> bool:
+        calls.append(ref)
+        return ref == "refs/remotes/origin/main"
+
+    monkeypatch.setattr(utils, "_git_ref_exists", fake_ref_exists)
+    monkeypatch.setattr(utils, "_extract_github_base_sha", lambda _env: None)
+    monkeypatch.setattr(utils, "_resolve_origin_head_ref", lambda _repo_path: None)
+
+    base_ref = utils._resolve_base_ref(Path("/tmp/repo"), diff_base=None, env={})
+
+    assert base_ref == "refs/remotes/origin/main"
+    assert "refs/remotes/origin/main" in calls
+    assert "origin/main" not in calls