diff --git a/src/io/metadata.cpp b/src/io/metadata.cpp
index 248feebabd29..d94b0ed3f2f7 100644
--- a/src/io/metadata.cpp
+++ b/src/io/metadata.cpp
@@ -510,7 +510,7 @@ void Metadata::InsertWeights(const label_t* weights, data_size_t start_index, da
 template <typename It>
 void Metadata::SetQueriesFromIterator(It first, It last) {
   std::lock_guard<std::mutex> lock(mutex_);
-  // Clear weights on empty input
+  // Clear query boundaries on empty input
   if (last - first == 0) {
     query_boundaries_.clear();
     num_queries_ = 0;
@@ -518,12 +518,12 @@ void Metadata::SetQueriesFromIterator(It first, It last) {
   }
 
   data_size_t sum = 0;
-  #pragma omp parallel for schedule(static) reduction(+:sum)
+  #pragma omp parallel for num_threads(OMP_NUM_THREADS()) schedule(static) reduction(+:sum)
   for (data_size_t i = 0; i < last - first; ++i) {
     sum += first[i];
   }
   if (num_data_ != sum) {
-    Log::Fatal("Sum of query counts differs from the length of #data");
+    Log::Fatal("Sum of query counts (%i) differs from the length of #data (%i)", num_data_, sum);
   }
   num_queries_ = last - first;
 
diff --git a/tests/python_package_test/test_arrow.py b/tests/python_package_test/test_arrow.py
index cd9fa4dcf678..dc482ecfdc2d 100644
--- a/tests/python_package_test/test_arrow.py
+++ b/tests/python_package_test/test_arrow.py
@@ -1,7 +1,6 @@
 # coding: utf-8
 import filecmp
-from pathlib import Path
-from typing import Any, Callable, Dict
+from typing import Any, Dict
 
 import numpy as np
 import pyarrow as pa
@@ -38,13 +37,13 @@ def generate_dummy_arrow_table() -> pa.Table:
     return pa.Table.from_arrays([col1, col2], names=["a", "b"])
 
 
-def generate_random_arrow_table(num_columns: int, num_datapoints: int, seed: int) -> pa.Table:
+def generate_random_arrow_table(num_columns, num_datapoints, seed) -> pa.Table:
     columns = [generate_random_arrow_array(num_datapoints, seed + i) for i in range(num_columns)]
     names = [f"col_{i}" for i in range(num_columns)]
     return pa.Table.from_arrays(columns, names=names)
 
 
-def generate_random_arrow_array(num_datapoints: int, seed: int) -> pa.ChunkedArray:
+def generate_random_arrow_array(num_datapoints, seed) -> pa.ChunkedArray:
     generator = np.random.default_rng(seed)
     data = generator.standard_normal(num_datapoints)
 
@@ -85,9 +84,7 @@ def dummy_dataset_params() -> Dict[str, Any]:
         (lambda: generate_random_arrow_table(100, 10000, 43), {}),
     ],
 )
-def test_dataset_construct_fuzzy(
-    tmp_path: Path, arrow_table_fn: Callable[[], pa.Table], dataset_params: Dict[str, Any]
-):
+def test_dataset_construct_fuzzy(tmp_path, arrow_table_fn, dataset_params):
     arrow_table = arrow_table_fn()
 
     arrow_dataset = lgb.Dataset(arrow_table, params=dataset_params)
@@ -108,7 +105,7 @@ def test_dataset_construct_fields_fuzzy():
     arrow_table = generate_random_arrow_table(3, 1000, 42)
     arrow_labels = generate_random_arrow_array(1000, 42)
     arrow_weights = generate_random_arrow_array(1000, 42)
-    arrow_groups = pa.chunked_array([[300, 400, 50], [250]], type=pa.uint8())
+    arrow_groups = pa.chunked_array([[300, 400, 50], [250]], type=pa.int32())
 
     arrow_dataset = lgb.Dataset(
         arrow_table, label=arrow_labels, weight=arrow_weights, group=arrow_groups
@@ -151,7 +148,7 @@ def test_dataset_construct_fields_fuzzy():
         pa.float64(),
     ],
 )
-def test_dataset_construct_labels(array_type: Any, label_data: Any, arrow_type: Any):
+def test_dataset_construct_labels(array_type, label_data, arrow_type):
     data = generate_dummy_arrow_table()
     labels = array_type(label_data, type=arrow_type)
     dataset = lgb.Dataset(data, label=labels, params=dummy_dataset_params())
@@ -178,7 +175,7 @@ def test_dataset_construct_weights_none():
     [(pa.array, [3, 0.7, 1.5, 0.5, 0.1]), (pa.chunked_array, [[3], [0.7, 1.5, 0.5, 0.1]])],
 )
 @pytest.mark.parametrize("arrow_type", [pa.float32(), pa.float64()])
-def test_dataset_construct_weights(array_type: Any, weight_data: Any, arrow_type: Any):
+def test_dataset_construct_weights(array_type, weight_data, arrow_type):
     data = generate_dummy_arrow_table()
     weights = array_type(weight_data, type=arrow_type)
     dataset = lgb.Dataset(data, weight=weights, params=dummy_dataset_params())
@@ -207,7 +204,7 @@ def test_dataset_construct_weights(array_type: Any, weight_data: Any, arrow_type
         pa.uint64(),
     ],
 )
-def test_dataset_construct_groups(array_type: Any, group_data: Any, arrow_type: Any):
+def test_dataset_construct_groups(array_type, group_data, arrow_type):
     data = generate_dummy_arrow_table()
     groups = array_type(group_data, type=arrow_type)
     dataset = lgb.Dataset(data, group=groups, params=dummy_dataset_params())