feat: implement local code scout, training pipeline, and MCP tools

tests/test_data.py

@@ -0,0 +1,52 @@
+import json
+
+import pytest
+
+from micro_scout.data import audit_splits, prepare
+from micro_scout.io import write_jsonl
+
+
+def test_overlap_audit_rejects_renamed_clones(tmp_path):
+    for split in ("train", "validation", "test"):
+        write_jsonl(
+            tmp_path / f"{split}.jsonl",
+            [
+                {
+                    "id": split,
+                    "repo": split,
+                    "code_hash": split,
+                    "query_hash": split,
+                    "structural_hash": "same-shape",
+                }
+            ],
+        )
+    with pytest.raises(ValueError, match="structural_hash"):
+        audit_splits(tmp_path)
+
+
+def test_overlap_audit_passes_disjoint_records(tmp_path):
+    for split in ("train", "validation", "test"):
+        write_jsonl(
+            tmp_path / f"{split}.jsonl",
+            [{key: split for key in ("id", "repo", "code_hash", "query_hash", "structural_hash")}],
+        )
+    assert set(audit_splits(tmp_path).values()) == {0}
+
+
+def test_dataset_failure_does_not_publish_partial_output(tmp_path):
+    pytest.importorskip("pyarrow")
+    output = tmp_path / "prepared"
+    with pytest.raises(FileNotFoundError):
+        prepare(tmp_path / "missing", output, {"train": 10, "validation": 10, "test": 10})
+    assert not output.exists()
+    assert not list(tmp_path.glob(".prepare-*"))
+
+
+def test_json_writer_rejects_non_finite_metrics(tmp_path):
+    from micro_scout.io import atomic_json
+
+    destination = tmp_path / "metrics.json"
+    atomic_json(destination, {"score": 1.0})
+    with pytest.raises(ValueError):
+        atomic_json(destination, {"score": float("nan")})
+    assert json.loads(destination.read_text()) == {"score": 1.0}