MAINT: make test code a little more explicit in what's done.

Author: mhvk

lib/matplotlib/tests/test_axes.py

@@ -4532,10 +4532,10 @@ def test_errorbar_nan(fig_test, fig_ref):
     xs = range(5)
     ys = np.array([1, 2, np.nan, np.nan, 3])
     es = np.array([4, 5, np.nan, np.nan, 6])
-    ax.errorbar(xs, ys, es)
+    ax.errorbar(xs, ys, yerr=es)
     ax = fig_ref.add_subplot()
-    ax.errorbar([0, 1], [1, 2], [4, 5])
-    ax.errorbar([4], [3], [6], fmt="C0")
+    ax.errorbar([0, 1], [1, 2], yerr=[4, 5])
+    ax.errorbar([4], [3], yerr=[6], fmt="C0")
 
 
 @check_figures_equal()
@@ -4545,10 +4545,10 @@ def test_errorbar_masked_negative(fig_test, fig_ref):
     mask = np.array([False, False, True, True, False])
     ys = np.ma.array([1, 2, 2, 2, 3], mask=mask)
     es = np.ma.array([4, 5, -1, -10, 6], mask=mask)
-    ax.errorbar(xs, ys, es)
+    ax.errorbar(xs, ys, yerr=es)
     ax = fig_ref.add_subplot()
-    ax.errorbar([0, 1], [1, 2], [4, 5])
-    ax.errorbar([4], [3], [6], fmt="C0")
+    ax.errorbar([0, 1], [1, 2], yerr=[4, 5])
+    ax.errorbar([4], [3], yerr=[6], fmt="C0")
 
 
 @image_comparison(['hist_stacked_stepfilled.png', 'hist_stacked_stepfilled.png'])