Add test to validate xtick alignment for scatter and line plots

This test ensures that the x-axis ticks are consistent between scatter and line plots when sharing the same axis. It addresses a potential issue related to GH#61005, verifying proper rendering of datetime x-axis labels.

Author: MartinBraquet

pandas/tests/plotting/test_series.py

@@ -971,3 +971,17 @@ def test_secondary_y_subplot_axis_labels(self):
         s1.plot(ax=ax2)
         assert len(ax.xaxis.get_minor_ticks()) == 0
         assert len(ax.get_xticklabels()) > 0
+
+    def test_scatter_line_xticks(self):
+        # GH#61005
+        datetime_list = [datetime(year=2025, month=1, day=1, hour=n) for n in range(3)]
+        df = DataFrame(columns=["datetime", "y"])
+        for i, n in enumerate(datetime_list):
+            df.loc[len(df)] = [n, i]
+        fig, ax = plt.subplots(2, sharex=True)
+        df.plot.scatter(x="datetime", y="y", ax=ax[0])
+        scatter_xticks = ax[0].get_xticks()
+        df.plot(x="datetime", y="y", ax=ax[1])
+        line_xticks = ax[1].get_xticks()
+        assert scatter_xticks[0] == line_xticks[0]
+        assert scatter_xticks[-1] == line_xticks[-1]