rewrite phase 1

tests/test_codegraph.py

@@ -1,13 +1,17 @@
 from pathlib import Path
 
-from agentci.adapters.codegraph import CodeGraphClient
+import pytest
+
+from agentci.codegraph import CodeGraph, CodeGraphError
 
 
 class FakeProcess:
-    returncode = 0
+    def __init__(self, returncode: int = 0, stderr: bytes = b"") -> None:
+        self.returncode = returncode
+        self.stderr = stderr
 
     async def communicate(self) -> tuple[bytes, bytes]:
-        return b"", b""
+        return b"", self.stderr
 
 
 async def test_initializes_incomplete_index_and_excludes_it_from_git(
@@ -23,11 +27,11 @@ async def test_initializes_incomplete_index_and_excludes_it_from_git(
         return FakeProcess()
 
     monkeypatch.setattr(
-        "agentci.adapters.codegraph.asyncio.create_subprocess_exec",
+        "agentci.codegraph.asyncio.create_subprocess_exec",
         create_subprocess_exec,
     )
 
-    await CodeGraphClient().prepare(workspace)
+    await CodeGraph().prepare(workspace)
 
     assert calls == [("codegraph", "init", str(workspace))]
     assert (workspace / ".git" / "info" / "exclude").read_text() == ".codegraph/\n"
@@ -49,11 +53,86 @@ async def test_syncs_an_existing_index_without_duplicating_exclude(
         return FakeProcess()
 
     monkeypatch.setattr(
-        "agentci.adapters.codegraph.asyncio.create_subprocess_exec",
+        "agentci.codegraph.asyncio.create_subprocess_exec",
         create_subprocess_exec,
     )
 
-    await CodeGraphClient().prepare(workspace)
+    await CodeGraph().prepare(workspace)
 
     assert calls == [("codegraph", "sync", str(workspace))]
     assert exclude.read_text() == "# local excludes\n.codegraph/\n"
+
+
+@pytest.mark.parametrize(
+    ("initial", "expected"),
+    [
+        ("*.pyc", "*.pyc\n.codegraph/\n"),
+        ("# .codegraph/ is documented here\n", "# .codegraph/ is documented here\n.codegraph/\n"),
+        ("  .codegraph/  \n", "  .codegraph/  \n"),
+    ],
+)
+async def test_handles_exclude_file_boundaries(
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+    initial: str,
+    expected: str,
+) -> None:
+    workspace = tmp_path / "repo"
+    exclude = workspace / ".git" / "info" / "exclude"
+    exclude.parent.mkdir(parents=True)
+    exclude.write_text(initial)
+
+    async def create_subprocess_exec(*_args, **_kwargs):
+        return FakeProcess()
+
+    monkeypatch.setattr(
+        "agentci.codegraph.asyncio.create_subprocess_exec",
+        create_subprocess_exec,
+    )
+
+    await CodeGraph().prepare(workspace)
+
+    assert exclude.read_text() == expected
+
+
+async def test_reports_missing_executable(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    workspace = tmp_path / "repo"
+    workspace.mkdir()
+
+    async def create_subprocess_exec(*_args, **_kwargs):
+        raise FileNotFoundError(2, "No such file or directory", "codegraph")
+
+    monkeypatch.setattr(
+        "agentci.codegraph.asyncio.create_subprocess_exec",
+        create_subprocess_exec,
+    )
+
+    with pytest.raises(CodeGraphError, match="Could not run CodeGraph:.*codegraph") as raised:
+        await CodeGraph().prepare(workspace)
+
+    assert isinstance(raised.value.__cause__, FileNotFoundError)
+    assert (workspace / ".git" / "info" / "exclude").read_text() == ".codegraph/\n"
+
+
+async def test_reports_nonzero_exit_with_bounded_non_utf8_stderr(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    workspace = tmp_path / "repo"
+    workspace.mkdir()
+    stderr = b"discarded-prefix" + (b"x" * 1200) + b"\xff useful-tail"
+
+    async def create_subprocess_exec(*_args, **_kwargs):
+        return FakeProcess(returncode=7, stderr=stderr)
+
+    monkeypatch.setattr(
+        "agentci.codegraph.asyncio.create_subprocess_exec",
+        create_subprocess_exec,
+    )
+
+    with pytest.raises(CodeGraphError, match="codegraph init failed") as raised:
+        await CodeGraph().prepare(workspace)
+
+    message = str(raised.value)
+    assert "discarded-prefix" not in message
+    assert "useful-tail" in message
+    assert len(message.removeprefix("codegraph init failed: ")) == 1000