Raise ValueError instead of IndexError in extract_json() (#941)

* Fix exception assertion

* Raise ValueError instead of IndexError in extract_json()

* Make flake8 happy

telescope/utils.py

@@ -281,7 +281,10 @@ def extract_json(path, data):
                 istep = int(step)
             except ValueError:
                 raise ValueError(str(ke))  # Original error with step as string
-            data = data[istep]
+            try:
+                data = data[istep]
+            except IndexError:
+                raise ValueError(str(ke))  # Original error with step as string
     return data
 
 

tests/test_utils.py

@@ -61,9 +61,17 @@ def test_extract_json():
     assert extract_json(".pings.0", data) == 314
     assert extract_json(".min_timestamp", data) == "2020-09-24T10:29:44.925"
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError) as exc_info:
         extract_json(".pings.a", data)
+    assert str(exc_info.value) == "list indices must be integers or slices, not str"
+
+    with pytest.raises(ValueError) as exc_info:
         extract_json(".field", "An error returned by check")
+    assert str(exc_info.value) == "string indices must be integers"
+
+    with pytest.raises(ValueError) as exc_info:
+        extract_json(".percentiles.75.value", {"percentiles": "No results"})
+    assert str(exc_info.value) == "string indices must be integers"
 
 
 async def test_bugzilla_fetch_fallsback_to_empty_list(mock_aioresponses, config):