Add other test from group TestInfer*

python/pyarrow/_pyarrow_cpp_tests.pyx

@@ -40,6 +40,7 @@ def test_PythonDecimalToString():
 
     assert string_result == decimal_string
 
+
 def test_InferPrecisionAndScale():
     cdef:
         c_string decimal_string = b'-394029506937548693.42983'
@@ -55,6 +56,7 @@ def test_InferPrecisionAndScale():
     assert expected_precision == metadata.precision()
     assert expected_scale == metadata.scale()
 
+
 def test_InferPrecisionAndNegativeScale():
     cdef:
         c_string decimal_string = b'-3.94042983E+10'
@@ -69,3 +71,51 @@ def test_InferPrecisionAndNegativeScale():
 
     assert expected_precision == metadata.precision()
     assert expected_scale == metadata.scale()
+
+
+def test_TestInferAllLeadingZeros():
+    cdef:
+        c_string decimal_string = b'0.001'
+        PyObject* python_object = DecimalFromString(<PyObject*>Decimal, decimal_string)
+        DecimalMetadata metadata
+        int32_t expected_precision = 3
+        int32_t expected_scale = 3
+
+    check_status(metadata.Update(
+        python_object)
+    )
+
+    assert expected_precision == metadata.precision()
+    assert expected_scale == metadata.scale()
+
+
+def test_TestInferAllLeadingZerosExponentialNotationPositive():
+    cdef:
+        c_string decimal_string = b'0.01E5'
+        PyObject* python_object = DecimalFromString(<PyObject*>Decimal, decimal_string)
+        DecimalMetadata metadata
+        int32_t expected_precision = 4
+        int32_t expected_scale = 0
+
+    check_status(metadata.Update(
+        python_object)
+    )
+
+    assert expected_precision == metadata.precision()
+    assert expected_scale == metadata.scale()
+
+
+def test_TestInferAllLeadingZerosExponentialNotationNegative():
+    cdef:
+        c_string decimal_string = b'0.01E3'
+        PyObject* python_object = DecimalFromString(<PyObject*>Decimal, decimal_string)
+        DecimalMetadata metadata
+        int32_t expected_precision = 2
+        int32_t expected_scale = 0
+
+    check_status(metadata.Update(
+        python_object)
+    )
+
+    assert expected_precision == metadata.precision()
+    assert expected_scale == metadata.scale()

python/pyarrow/tests/test_python.py

@@ -30,18 +30,28 @@
 #         if callable(item) and name.startswith("test_"):
 #             setattr(sys.modules[__name__], name, item)
 
-from pyarrow._pyarrow_cpp_tests import (test_PythonDecimalToString,  # noqa
-                                        test_InferPrecisionAndScale,
-                                        test_InferPrecisionAndNegativeScale)
+import pyarrow._pyarrow_cpp_tests as t # noqa
 
 
 def test_python_decimal_to_string():
-    test_PythonDecimalToString()
+    t.test_PythonDecimalToString()
 
 
 def test_infer_precision_and_scale():
-    test_InferPrecisionAndScale()
+    t.test_InferPrecisionAndScale()
 
 
 def test_infer_precision_and_negative_scale():
-    test_InferPrecisionAndNegativeScale()
+    t.test_InferPrecisionAndNegativeScale()
+
+
+def test_infer_all_leading_zeros():
+    t.test_TestInferAllLeadingZeros()
+
+
+def test_infer_all_leading_zeros_e_pos():
+    t.test_TestInferAllLeadingZerosExponentialNotationPositive()
+
+
+def test_infer_all_leading_zeros_e_neg():
+    t.test_TestInferAllLeadingZerosExponentialNotationNegative()