diff --git a/DeepDataMiningLearning/ngperception/detection/kitti_eval/eval.py b/DeepDataMiningLearning/ngperception/detection/kitti_eval/eval.py
index 958fa525..45b54a40 100644
--- a/DeepDataMiningLearning/ngperception/detection/kitti_eval/eval.py
+++ b/DeepDataMiningLearning/ngperception/detection/kitti_eval/eval.py
@@ -649,7 +649,7 @@ def get_official_eval_result(gt_annos, dt_annos, current_classes, class_to_name=
             0: 'Car',
             1: 'Pedestrian',
             2: 'Cyclist',
-            3: 'Sign', #'Van',
+            3: 'Van',
             4: 'Person_sitting',
             5: 'Truck'
         }
diff --git a/DeepDataMiningLearning/ngperception/detection/kitti_eval/tests/test_class_names_agree.py b/DeepDataMiningLearning/ngperception/detection/kitti_eval/tests/test_class_names_agree.py
new file mode 100644
index 00000000..6ac4c9d9
--- /dev/null
+++ b/DeepDataMiningLearning/ngperception/detection/kitti_eval/tests/test_class_names_agree.py
@@ -0,0 +1,125 @@
+"""The class index -> name maps in eval.py have to agree with the filter.
+
+`clean_data` decides which annotations belong to a class index, from
+
+    CLASS_NAMES = ['car', 'pedestrian', 'cyclist', 'van', 'person_sitting', 'truck']
+
+and two other maps in the same file turn indices into the names that appear in
+the results and accept class names from callers: one in
+`get_official_eval_result`, one in `get_coco_eval_result`. If those disagree
+with `CLASS_NAMES`, a result is filed under a class it was not measured on, and
+a caller naming a class gets a different one -- or a KeyError.
+
+Reads the source with `ast` rather than importing it: eval.py compiles its
+kernels with `@numba.jit` at import, and this makes no claim about numba.
+Standard library only, no dataset, no GPU.
+
+    pytest DeepDataMiningLearning/ngperception/detection/kitti_eval/tests
+"""
+import ast
+import io
+from pathlib import Path
+
+import pytest
+
+EVAL_PY = Path(__file__).resolve().parents[1] / "eval.py"
+
+
+def _tree():
+    return ast.parse(io.open(EVAL_PY, encoding="utf-8", errors="replace").read())
+
+
+def _class_names():
+    """CLASS_NAMES as assigned inside clean_data."""
+    for node in ast.walk(_tree()):
+        if isinstance(node, ast.FunctionDef) and node.name == "clean_data":
+            for stmt in node.body:
+                if (isinstance(stmt, ast.Assign)
+                        and getattr(stmt.targets[0], "id", None) == "CLASS_NAMES"):
+                    return ast.literal_eval(stmt.value)
+    pytest.fail("clean_data no longer assigns CLASS_NAMES")
+
+
+def _index_maps():
+    """Every `class_to_name = {...}` literal, keyed by the function holding it."""
+    maps = {}
+    for node in ast.walk(_tree()):
+        if not isinstance(node, ast.FunctionDef):
+            continue
+        for stmt in ast.walk(node):
+            if (isinstance(stmt, ast.Assign)
+                    and getattr(stmt.targets[0], "id", None) == "class_to_name"
+                    and isinstance(stmt.value, ast.Dict)):
+                try:
+                    maps[node.name] = ast.literal_eval(stmt.value)
+                except ValueError:
+                    pass
+    return maps
+
+
+def test_the_file_is_where_it_is_expected():
+    assert EVAL_PY.is_file()
+
+
+def test_clean_data_still_defines_the_filter_list():
+    names = _class_names()
+    assert names[:3] == ["car", "pedestrian", "cyclist"]
+    assert len(names) == 6
+
+
+def test_both_index_maps_were_found():
+    maps = _index_maps()
+    assert "get_official_eval_result" in maps
+    assert "get_coco_eval_result" in maps
+
+
+@pytest.mark.parametrize("func", ["get_official_eval_result", "get_coco_eval_result"])
+def test_every_index_names_the_class_clean_data_filters_for(func):
+    names = _class_names()
+    mapping = _index_maps()[func]
+    mismatches = [
+        f"{i}: filter={names[i]!r} label={label!r}"
+        for i, label in sorted(mapping.items())
+        if i < len(names) and label.lower() != names[i]
+    ]
+    assert mismatches == []
+
+
+def test_the_two_maps_agree_with_each_other():
+    a = _index_maps()["get_official_eval_result"]
+    b = _index_maps()["get_coco_eval_result"]
+    shared = set(a) & set(b)
+    assert shared, "the two maps share no index"
+    assert [i for i in sorted(shared) if a[i] != b[i]] == []
+
+
+@pytest.mark.parametrize("func", ["get_official_eval_result", "get_coco_eval_result"])
+def test_a_caller_can_name_every_class_the_filter_accepts(func):
+    """`name_to_class` is built by inverting the map; a caller passes a name."""
+    names = _class_names()
+    mapping = _index_maps()[func]
+    name_to_class = {v: k for k, v in mapping.items()}
+    for i in sorted(mapping):
+        if i >= len(names):
+            continue
+        assert any(k.lower() == names[i] for k in name_to_class), (
+            f"no caller-facing name resolves to {names[i]!r} (index {i})"
+        )
+
+
+def test_no_index_map_carries_a_class_kitti_does_not_have():
+    """`Sign` is a Waymo class. waymo2kitti_async.py:87 says so: 'not in kitti'."""
+    names = {n.lower() for n in _class_names()}
+    strays = []
+    for func, mapping in _index_maps().items():
+        for i, label in sorted(mapping.items()):
+            if i < len(_class_names()) and label.lower() not in names:
+                strays.append(f"{func}[{i}] = {label!r}")
+    assert strays == []
+
+
+def test_the_inverted_map_has_no_duplicate_names():
+    """Two indices sharing a name would make the caller's choice ambiguous."""
+    for func, mapping in _index_maps().items():
+        labels = [v for _, v in sorted(mapping.items())]
+        assert len(labels) == len(set(labels)), f"{func} repeats a name"