Fix quantization tools for issue #19529 (#19591)

### Description
Fix issue #19529, the code was using a variable loop outside a loop.

onnxruntime/python/tools/quantization/calibrate.py

@@ -733,13 +733,11 @@ def collect_absolute_value(self, name_to_arr):
         for tensor, data_arr in name_to_arr.items():
             if isinstance(data_arr, list):
                 for arr in data_arr:
-                    if not isinstance(arr, np.ndarray):
-                        raise ValueError(f"Unexpected type {type(arr)} for tensor={tensor!r}")
-                dtypes = set(a.dtype for a in arr)
-                if len(dtypes) != 1:
-                    raise ValueError(
-                        f"The calibration expects only one element type but got {dtypes} for tensor={tensor!r}"
-                    )
+                    assert isinstance(arr, np.ndarray), f"Unexpected type {type(arr)} for tensor={tensor!r}"
+                dtypes = set(a.dtype for a in data_arr)
+                assert (
+                    len(dtypes) == 1
+                ), f"The calibration expects only one element type but got {dtypes} for tensor={tensor!r}"
                 data_arr_np = np.asarray(data_arr)
             elif not isinstance(data_arr, np.ndarray):
                 raise ValueError(f"Unexpected type {type(data_arr)} for tensor={tensor!r}")

onnxruntime/test/python/quantization/test_quant_issues.py

@@ -0,0 +1,72 @@
+# -------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for
+# license information.
+# --------------------------------------------------------------------------
+import os
+import tempfile
+import unittest
+import warnings
+
+
+def ignore_warnings(warns):
+    """
+    Catches warnings.
+
+    :param warns:   warnings to ignore
+    """
+
+    def wrapper(fct):
+        if warns is None:
+            raise AssertionError(f"warns cannot be None for '{fct}'.")
+
+        def call_f(self):
+            with warnings.catch_warnings():
+                warnings.simplefilter("ignore", warns)
+                return fct(self)
+
+        return call_f
+
+    return wrapper
+
+
+class TestQuantIssues(unittest.TestCase):
+    @ignore_warnings(DeprecationWarning)
+    def test_minimal_model(self):
+        folder = os.path.join(os.path.dirname(__file__), "..", "..", "testdata")
+        onnx_path = os.path.join(folder, "qdq_minimal_model.onnx")
+        if not os.path.exists(onnx_path):
+            # The file does seem to be the same location in every CI job.
+            raise unittest.SkipTest("unable to find {onnx_path!r}")
+
+        import numpy as np
+
+        import onnxruntime.quantization as oq
+
+        class Mock:
+            def __init__(self):
+                self.i = 0
+
+            def get_next(self):
+                if self.i > 10:
+                    return None
+                self.i += 1
+                return {"input": np.random.randint(0, 255, size=(1, 3, 32, 32), dtype=np.uint8)}
+
+        with tempfile.TemporaryDirectory() as temp:
+            preprocessed_path = os.path.join(temp, "preprocessed.onnx")
+            quantized_path = os.path.join(temp, "quantized.onnx")
+            oq.quant_pre_process(onnx_path, preprocessed_path, skip_symbolic_shape=True)
+            oq.quantize_static(
+                preprocessed_path,
+                quantized_path,
+                Mock(),
+                calibrate_method=oq.CalibrationMethod.Percentile,
+                op_types_to_quantize=["Conv", "Mul", "Gemm"],
+            )
+            assert os.path.exists(preprocessed_path), f"missing output {preprocessed_path!r}"
+            assert os.path.exists(quantized_path), f"missing output {quantized_path!r}"
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)