fixup! ENH/API: ExtensionArray.factorize

Author: TomAugspurger

pandas/tests/extension/json/array.py

@@ -111,7 +111,7 @@ def factorize(self, na_sentinel=-1):
 
         # fixup NA
         if self.isna().any():
-            na_code = self.isna().argmax()
+            na_code = labels[self.isna()][0]
 
             labels[labels == na_code] = na_sentinel
             labels[labels > na_code] -= 1

pandas/tests/extension/json/test_json.py

@@ -75,10 +75,8 @@ class TestMissing(base.BaseMissingTests):
 
 
 class TestMethods(base.BaseMethodsTests):
-    unhashable = pytest.mark.skip(reason="Unhashable")
-
-    @unhashable
-    def test_factorize(self):
+    @pytest.mark.skip(reason="Unhashable")
+    def test_value_counts(self):
         pass