DataFrame pivot_table nunique aggfunc test GH#29080

Signed-off-by: Liang Yan <[email protected]>

Author: liang3zy22

pandas/tests/reshape/test_pivot.py

@@ -2378,6 +2378,61 @@ def test_pivot_table_with_mixed_nested_tuples(self, using_array_manager):
             expected["small"] = expected["small"].astype("int64")
         tm.assert_frame_equal(result, expected)
 
+    def test_pivot_table_aggfunc_nunique_with_different_values(self):
+        np.random.seed(0)
+        test = DataFrame(
+            {
+                "a": np.random.randint(0, 10, size=(10,)),
+                "b": np.random.randint(0, 10, size=(10,)),
+                "c": np.random.randint(0, 10, size=(10,)),
+                "d": np.random.randint(0, 10, size=(10,)),
+            }
+        )
+        a = test["a"]
+        b = test["b"]
+        c = test["c"]
+        dictionary = {}
+        for x, y, z in np.nditer([a, b, c]):
+            xv = x.item()
+            yv = y.item()
+            zv = z.item()
+            if (xv, yv) in dictionary:
+                dictionary[(xv, yv)] += [zv]
+            else:
+                dictionary[(xv, yv)] = [zv]
+
+        for key in dictionary:
+            dictionary[key] = float(len(set(dictionary[key])))
+
+        indarr = np.sort(a.unique())
+        barr = np.sort(b.unique())
+        columnval = MultiIndex.from_arrays(
+            [
+                ["nunique" for i in range(barr.size)],
+                ["c" for i in range(barr.size)],
+                barr,
+            ],
+            names=(None, None, "b"),
+        )
+        nparr = np.full((indarr.size, barr.size), np.NaN)
+        expected = DataFrame(nparr, index=Index(indarr, name="a"), columns=columnval)
+        for key, value in dictionary.items():
+            expected.loc[key[0], ("nunique", "c", key[1])] = value
+        result = test.pivot_table(
+            index=[
+                "a",
+            ],
+            columns=[
+                "b",
+            ],
+            values=[
+                "c",
+            ],
+            aggfunc=["nunique"],
+        )
+
+        tm.assert_frame_equal(result, expected)
+
 
 class TestPivot:
     def test_pivot(self):