matplotlib · QuLogic · Dec 6, 2023 · Dec 2, 2023 · Dec 2, 2023 · Dec 2, 2023
diff --git a/lib/matplotlib/tests/test_datetime.py b/lib/matplotlib/tests/test_datetime.py
@@ -317,11 +317,40 @@ def test_fill_between(self):
         fig, ax = plt.subplots()
         ax.fill_between(...)
 
-    @pytest.mark.xfail(reason="Test for fill_betweenx not written yet")
     @mpl.style.context("default")
     def test_fill_betweenx(self):
-        fig, ax = plt.subplots()
-        ax.fill_betweenx(...)
+        mpl.rcParams["date.converter"] = "concise"
+        np.random.seed(19680801)
+
+        x_base_date = datetime.datetime(2023, 1, 1)
+        x_dates1 = [x_base_date]
+        for i in range(1, 10):
+            x_base_date += datetime.timedelta(days=np.random.randint(1, 5))
+            x_dates1.append(x_base_date)
+
+        x_dates2 = [x_base_date]
+        for i in range(1, 10):
+            x_base_date += datetime.timedelta(days=np.random.randint(1, 5))
+            x_dates2.append(x_base_date)
+        y_values = np.random.rand(10) * 10
+        y_values.sort()
+
+        x_values1 = np.random.rand(10) * 10
+        x_values2 = x_values1 + np.random.rand(10) * 10
+        x_values1.sort()
+        x_values2.sort()
+
+        y_base_date = datetime.datetime(2023, 1, 1)
+        y_dates = [y_base_date]
+        for i in range(1, 10):
+            y_base_date += datetime.timedelta(days=np.random.randint(1, 10))
+            y_dates.append(y_base_date)
+
+        fig, (ax1, ax2, ax3) = plt.subplots(1, 3, layout="constrained")
+
+        ax1.fill_betweenx(y_values, x_dates1, x_dates2)
+        ax2.fill_betweenx(y_dates, x_values1, x_values2)
+        ax3.fill_betweenx(y_dates, x_dates1, x_dates2)
 
     @pytest.mark.xfail(reason="Test for hexbin not written yet")
     @mpl.style.context("default")