diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
index 1e549feda3d0..393bec8a923f 100644
--- a/lib/matplotlib/tests/test_axes.py
+++ b/lib/matplotlib/tests/test_axes.py
@@ -3642,14 +3642,14 @@ def test_step_linestyle():
         ax.set_ylim([-1, 7])
 
     # Reuse testcase from above for a labeled data test
-    data = {"x": x, "y": y, "y1": y+1, "y2": y+2}
+    data = {"X": x, "Y0": y, "Y1": y+1, "Y2": y+2}
     fig, ax_lst = plt.subplots(2, 2)
     ax_lst = ax_lst.flatten()
     ln_styles = ['-', '--', '-.', ':']
     for ax, ls in zip(ax_lst, ln_styles):
-        ax.step("x", "y", lw=5, linestyle=ls, where='pre', data=data)
-        ax.step("x", "y1", lw=5, linestyle=ls, where='mid', data=data)
-        ax.step("x", "y2", lw=5, linestyle=ls, where='post', data=data)
+        ax.step("X", "Y0", lw=5, linestyle=ls, where='pre', data=data)
+        ax.step("X", "Y1", lw=5, linestyle=ls, where='mid', data=data)
+        ax.step("X", "Y2", lw=5, linestyle=ls, where='post', data=data)
         ax.set_xlim([-1, 5])
         ax.set_ylim([-1, 7])