TST: Addition test for get_indexer for interval index (#47816)

* TST: Addition test for get_indexer for interval index

* TST: Moved tests to interval and fixed pre-commit issue

* TST: Changed to assert numpy array equals

* TST: Moved test to test_indexing

Author: parthi-siva

pandas/tests/indexes/interval/test_indexing.py

@@ -15,7 +15,11 @@
     NaT,
     Series,
     Timedelta,
+    Timestamp,
+    array,
     date_range,
+    interval_range,
+    period_range,
     timedelta_range,
 )
 import pandas._testing as tm
@@ -415,6 +419,16 @@ def test_get_indexer_multiindex_with_intervals(self):
         expected = np.array([1, 4, 7], dtype=np.intp)
         tm.assert_numpy_array_equal(result, expected)
 
+    @pytest.mark.parametrize("box", [IntervalIndex, array, list])
+    def test_get_indexer_interval_index(self, box):
+        # GH#30178
+        rng = period_range("2022-07-01", freq="D", periods=3)
+        idx = box(interval_range(Timestamp("2022-07-01"), freq="3D", periods=3))
+
+        actual = rng.get_indexer(idx)
+        expected = np.array([-1, -1, -1], dtype=np.intp)
+        tm.assert_numpy_array_equal(actual, expected)
+
 
 class TestSliceLocs:
     def test_slice_locs_with_interval(self):