BUG: update tests (pandas-dev#39189)

Author: nofarmish

Diff for: pandas/core/computation/pytables.py

@@ -11,6 +11,7 @@
 from pandas.compat.chainmap import DeepChainMap
 
 from pandas.core.dtypes.common import is_list_like
+from pandas.core.series import Series
 
 import pandas.core.common as com
 from pandas.core.computation import expr, ops, scope as _scope
@@ -209,12 +210,8 @@ def stringify(value):
                 v = Timedelta(v, unit="s").value
             return TermValue(int(v), v, kind)
         elif meta == "category":
-            metadata = extract_array(self.metadata, extract_numpy=True)
-            if v not in metadata:
-                result = -1
-            else:
-                result = metadata.searchsorted(v, side="left")
-            return TermValue(result, result, "integer")
+            term_value = self._convert_category_value(self.metadata, v)
+            return term_value
         elif kind == "integer":
             v = int(float(v))
             return TermValue(v, v, kind)
@@ -243,6 +240,15 @@ def stringify(value):
         else:
             raise TypeError(f"Cannot compare {v} of type {type(v)} to {kind} column")
 
+    @staticmethod
+    def _convert_category_value(metadata: Series, value: Any) -> TermValue:
+        metadata = extract_array(metadata, extract_numpy=True)
+        if value not in metadata:
+            result = -1
+        else:
+            result = metadata.searchsorted(value, side="left")
+        return TermValue(result, result, "integer")
+
     def convert_values(self):
         pass
 

Diff for: pandas/tests/computation/test_pytables.py

@@ -0,0 +1,22 @@
+from typing import Any
+import pytest
+import numpy as np
+
+from pandas.core.computation.pytables import TermValue, BinOp
+from pandas import Series
+
+
+@pytest.mark.parametrize(
+    "value, expected_results",
+    [("q", TermValue(-1, -1, "integer")), ("a", TermValue(0, 0, "integer"))],
+)
+def test__convert_value(value: Any, expected_results: TermValue):
+    metadata = Series(np.array(['a', 'b', 's']))
+
+    result = BinOp._convert_category_value(metadata, value)
+
+    assert (
+        result.kind == expected_results.kind
+        and result.value == expected_results.value
+        and result.converted == expected_results.converted
+    )