From d96219a1ffdf2dd776b6fb898d1b2391d01f79da Mon Sep 17 00:00:00 2001
From: QuadroTec <19280099+QuadroTec@users.noreply.github.com>
Date: Tue, 17 Oct 2023 14:31:33 +1100
Subject: [PATCH 1/3] add test_stackplot in test_datetime.py

---
 lib/matplotlib/tests/test_datetime.py | 35 ++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/lib/matplotlib/tests/test_datetime.py b/lib/matplotlib/tests/test_datetime.py
index ef83b837348d..f17700dc2395 100644
--- a/lib/matplotlib/tests/test_datetime.py
+++ b/lib/matplotlib/tests/test_datetime.py
@@ -318,11 +318,40 @@ def test_spy(self):
         fig, ax = plt.subplots()
         ax.spy(...)
 
-    @pytest.mark.xfail(reason="Test for stackplot not written yet")
     @mpl.style.context("default")
     def test_stackplot(self):
-        fig, ax = plt.subplots()
-        ax.stackplot(...)
+        mpl.rcParams["date.converter"] = 'concise'
+        N = 10
+        fig, (ax1, ax2) = plt.subplots(2, 1, constrained_layout=True)
+
+        stacked_nums = np.array([range(1, N)] * 4)
+
+        dates_days = np.array(
+            [datetime.datetime(2023, 1, i) for i in range(1, N)]
+        )
+        dates_years = np.array(
+            [datetime.datetime(1970 + i, 1, 1) for i in range(1, N)]
+        )
+
+        timedelta_days = np.array(
+            [i * datetime.timedelta(days=1) for i in range(1, N)]
+        )
+        timedelta_hours = np.array(
+            [i * datetime.timedelta(hours=24) for i in range(1, N)]
+        )
+        timedelta_seconds = np.array(
+            [i * datetime.timedelta(seconds=86400) for i in range(1, N)]
+        )
+
+        ax1.stackplot(dates_years, stacked_nums)
+
+        ax2.stackplot(
+            dates_days, dates_days, timedelta_days, timedelta_hours, timedelta_seconds
+        )
+        ax2.set_ylim(
+            datetime.datetime(2022, 12, 31),
+            datetime.datetime(2023, 2, 8)
+        )
 
     @pytest.mark.xfail(reason="Test for stairs not written yet")
     @mpl.style.context("default")

From 3cf5376844bf252e7c754a87c13a7d747bde6d2b Mon Sep 17 00:00:00 2001
From: QuadroTec <19280099+QuadroTec@users.noreply.github.com>
Date: Tue, 17 Oct 2023 18:12:48 +1100
Subject: [PATCH 2/3] Remove stackplot test with datetime y-axis

---
 lib/matplotlib/tests/test_datetime.py | 30 +++------------------------
 1 file changed, 3 insertions(+), 27 deletions(-)

diff --git a/lib/matplotlib/tests/test_datetime.py b/lib/matplotlib/tests/test_datetime.py
index f17700dc2395..b3f0441f393f 100644
--- a/lib/matplotlib/tests/test_datetime.py
+++ b/lib/matplotlib/tests/test_datetime.py
@@ -322,36 +322,12 @@ def test_spy(self):
     def test_stackplot(self):
         mpl.rcParams["date.converter"] = 'concise'
         N = 10
-        fig, (ax1, ax2) = plt.subplots(2, 1, constrained_layout=True)
+        fig, ax = plt.subplots(constrained_layout=True)
 
         stacked_nums = np.array([range(1, N)] * 4)
+        dates = np.array([datetime.datetime(2020 + i, 1, 1) for i in range(N - 1)])
 
-        dates_days = np.array(
-            [datetime.datetime(2023, 1, i) for i in range(1, N)]
-        )
-        dates_years = np.array(
-            [datetime.datetime(1970 + i, 1, 1) for i in range(1, N)]
-        )
-
-        timedelta_days = np.array(
-            [i * datetime.timedelta(days=1) for i in range(1, N)]
-        )
-        timedelta_hours = np.array(
-            [i * datetime.timedelta(hours=24) for i in range(1, N)]
-        )
-        timedelta_seconds = np.array(
-            [i * datetime.timedelta(seconds=86400) for i in range(1, N)]
-        )
-
-        ax1.stackplot(dates_years, stacked_nums)
-
-        ax2.stackplot(
-            dates_days, dates_days, timedelta_days, timedelta_hours, timedelta_seconds
-        )
-        ax2.set_ylim(
-            datetime.datetime(2022, 12, 31),
-            datetime.datetime(2023, 2, 8)
-        )
+        ax.stackplot(dates, stacked_nums)
 
     @pytest.mark.xfail(reason="Test for stairs not written yet")
     @mpl.style.context("default")

From d21d836ece7fdc4943cd87a746f0e137c42d302c Mon Sep 17 00:00:00 2001
From: QuadroTec <19280099+QuadroTec@users.noreply.github.com>
Date: Wed, 18 Oct 2023 13:40:47 +1100
Subject: [PATCH 3/3] Refactor test_stackplot

---
 lib/matplotlib/tests/test_datetime.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/matplotlib/tests/test_datetime.py b/lib/matplotlib/tests/test_datetime.py
index b3f0441f393f..b21ff1bb7202 100644
--- a/lib/matplotlib/tests/test_datetime.py
+++ b/lib/matplotlib/tests/test_datetime.py
@@ -322,11 +322,10 @@ def test_spy(self):
     def test_stackplot(self):
         mpl.rcParams["date.converter"] = 'concise'
         N = 10
-        fig, ax = plt.subplots(constrained_layout=True)
-
-        stacked_nums = np.array([range(1, N)] * 4)
+        stacked_nums = np.tile(np.arange(1, N), (4, 1))
         dates = np.array([datetime.datetime(2020 + i, 1, 1) for i in range(N - 1)])
 
+        fig, ax = plt.subplots(layout='constrained')
         ax.stackplot(dates, stacked_nums)
 
     @pytest.mark.xfail(reason="Test for stairs not written yet")