add test_xer_yerr_positive

Author: Kislovskiy

lib/matplotlib/tests/test_axes.py

@@ -3513,6 +3513,18 @@ def test_errorbar_every_invalid():
         ax.errorbar(x, y, yerr, errorevery='foobar')
 
 
+def test_xerr_yerr_positive():
+    ax = plt.figure().subplots()
+
+    with pytest.raises(ValueError,
+                       match="'xerr' and 'yerr' must have positive numbers"):
+        ax.errorbar(x=[0], y=[0], xerr=[[-0.5], [1]], yerr=[[-0.5], [1]])
+    with pytest.raises(ValueError, match="'xerr' must have positive numbers"):
+        ax.errorbar(x=[0], y=[0], xerr=[[-0.5], [1]])
+    with pytest.raises(ValueError, match="'yerr' must have positive numbers"):
+        ax.errorbar(x=[0], y=[0], yerr=[[-0.5], [1]])
+
+
 @check_figures_equal()
 def test_errorbar_every(fig_test, fig_ref):
     x = np.linspace(0, 1, 15)