From 66be10c8b44ab18e3db2f748fee238d3c265b5f0 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Mon, 26 Aug 2019 17:37:54 -0700
Subject: [PATCH 1/2] BUG: fix+test Timestamp with int array

---
 pandas/_libs/tslibs/c_timestamp.pyx           | 16 ++++++
 .../tests/scalar/timestamp/test_arithmetic.py | 53 +++++++++++++++++++
 2 files changed, 69 insertions(+)

diff --git a/pandas/_libs/tslibs/c_timestamp.pyx b/pandas/_libs/tslibs/c_timestamp.pyx
index 906dabba09486..70b7fd7f1e9ee 100644
--- a/pandas/_libs/tslibs/c_timestamp.pyx
+++ b/pandas/_libs/tslibs/c_timestamp.pyx
@@ -251,6 +251,14 @@ cdef class _Timestamp(datetime):
                 result = result.normalize()
             return result
 
+        elif is_array(other):
+            if other.dtype.kind in ['i', 'u']:
+                maybe_integer_op_deprecated(self)
+                if self.freq is None:
+                    raise ValueError("Cannot add integer-dtype array "
+                                     "to Timestamp without freq.")
+                return self.freq * other + self
+
         # index/series like
         elif hasattr(other, '_typ'):
             return NotImplemented
@@ -268,6 +276,14 @@ cdef class _Timestamp(datetime):
             neg_other = -other
             return self + neg_other
 
+        elif is_array(other):
+            if other.dtype.kind in ['i', 'u']:
+                maybe_integer_op_deprecated(self)
+                if self.freq is None:
+                    raise ValueError("Cannot subtract integer-dtype array "
+                                     "from Timestamp without freq.")
+                return self - self.freq * other
+
         typ = getattr(other, '_typ', None)
 
         # a Timestamp-DatetimeIndex -> yields a negative TimedeltaIndex
diff --git a/pandas/tests/scalar/timestamp/test_arithmetic.py b/pandas/tests/scalar/timestamp/test_arithmetic.py
index 58bd03129f2df..e349399fbc151 100644
--- a/pandas/tests/scalar/timestamp/test_arithmetic.py
+++ b/pandas/tests/scalar/timestamp/test_arithmetic.py
@@ -151,3 +151,56 @@ def test_timestamp_add_timedelta64_unit(self, other, expected_difference):
         result = ts + other
         valdiff = result.value - ts.value
         assert valdiff == expected_difference
+
+    @pytest.mark.parametrize("ts", [Timestamp.now(), Timestamp.now("utc")])
+    @pytest.mark.parametrize(
+        "other",
+        [
+            1,
+            np.int64(1),
+            np.array([1, 2], dtype=np.int32),
+            np.array([3, 4], dtype=np.uint64),
+        ],
+    )
+    def test_add_int_no_freq(self, ts, other):
+        with pytest.raises(ValueError, match="without freq"):
+            ts + other
+        with pytest.raises(ValueError, match="without freq"):
+            other + ts
+
+        with pytest.raises(ValueError, match="without freq"):
+            ts - other
+        with pytest.raises(TypeError):
+            other - ts
+
+    @pytest.mark.parametrize(
+        "ts",
+        [
+            Timestamp("1776-07-04", freq="D"),
+            Timestamp("1776-07-04", tz="UTC", freq="D"),
+        ],
+    )
+    @pytest.mark.parametrize(
+        "other",
+        [
+            1,
+            np.int64(1),
+            np.array([1, 2], dtype=np.int32),
+            np.array([3, 4], dtype=np.uint64),
+        ],
+    )
+    def test_add_int_with_freq(self, ts, other):
+        with tm.assert_produces_warning(FutureWarning):
+            result1 = ts + other
+        with tm.assert_produces_warning(FutureWarning):
+            result2 = other + ts
+
+        assert np.all(result1 == result2)
+
+        with tm.assert_produces_warning(FutureWarning):
+            result = result1 - other
+
+        assert np.all(result == ts)
+
+        with pytest.raises(TypeError):
+            other - ts

From 3276aac874baae35d35be436930ee401ea808230 Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Mon, 26 Aug 2019 18:11:10 -0700
Subject: [PATCH 2/2] add _raises to test name

---
 pandas/tests/scalar/timestamp/test_arithmetic.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/tests/scalar/timestamp/test_arithmetic.py b/pandas/tests/scalar/timestamp/test_arithmetic.py
index e349399fbc151..2ef4fe79eeacf 100644
--- a/pandas/tests/scalar/timestamp/test_arithmetic.py
+++ b/pandas/tests/scalar/timestamp/test_arithmetic.py
@@ -162,7 +162,7 @@ def test_timestamp_add_timedelta64_unit(self, other, expected_difference):
             np.array([3, 4], dtype=np.uint64),
         ],
     )
-    def test_add_int_no_freq(self, ts, other):
+    def test_add_int_no_freq_raises(self, ts, other):
         with pytest.raises(ValueError, match="without freq"):
             ts + other
         with pytest.raises(ValueError, match="without freq"):