matplotlib
diff --git a/‎lib/matplotlib/tests/test_mutate_inputs.py
Lines changed: 0 additions & 112 deletions b/‎lib/matplotlib/tests/test_mutate_inputs.py
Lines changed: 0 additions & 112 deletions
diff --git a/‎lib/mpl_toolkits/mplot3d/tests/test_axes3d.py
Lines changed: 49 additions & 0 deletions b/‎lib/mpl_toolkits/mplot3d/tests/test_axes3d.py
Lines changed: 49 additions & 0 deletions
@@ -2124,3 +2124,52 @@ def test_panecolor_rcparams():
                          'axes3d.zaxis.panecolor': 'b'}):
         fig = plt.figure(figsize=(1, 1))
         fig.add_subplot(projection='3d')
+
+
+# test cases came from GH#8990
+@check_figures_equal(extensions=["png"])
+def test_mutating_input_arrays_y_and_z(fig_test, fig_ref):
+    ax1 = fig_test.add_subplot(111, projection='3d')
+    x = [1, 2, 3]
+    y = [0.0, 0.0, 0.0]
+    z = [0.0, 0.0, 0.0]
+    ax1.plot(x, y, z, 'o-')
+
+    ax1.set_ylim([0, 4])
+    ax1.set_zlim([0, 4])
+    fig_test.draw_without_rendering()
+
+    # mutate y,z to get a nontrivial line
+    y[:] = [1, 2, 3]
+    z[:] = [1, 2, 3]
+    fig_test.draw_without_rendering()
+
+    # draw the same plot without mutating x and y
+    ax2 = fig_ref.add_subplot(111, projection='3d')
+    x = [1, 2, 3]
+    y = [0.0, 0.0, 0.0]
+    z = [0.0, 0.0, 0.0]
+    ax2.plot(x, y, z, 'o-')
+
+    ax2.set_ylim([0, 4])
+    ax2.set_zlim([0, 4])
+
+
+# test cases came from GH#8990
+@check_figures_equal(extensions=["png"])
+def test_mutating_input_arrays_sin_3d(fig_test, fig_ref):
+    x = np.arange(0, 2*np.pi, 0.1)
+    v1 = np.zeros_like(x)
+    ax1 = fig_test.subplots(subplot_kw={'projection': '3d'})  # 3D plot
+    v1[:] = np.sin(x)
+    ax1.plot(x, v1, zs=1, zdir='y')
+    v1[:] = np.sin(5*x)
+    ax1.plot(x, v1, zs=2, zdir='y')
+
+    # plotting the same graph without changing any data
+    x1 = np.arange(0, 2*np.pi, 0.1)
+    v2 = np.sin(x1)
+    v3 = np.sin(5*x1)
+    ax2 = fig_ref.subplots(subplot_kw={'projection': '3d'})  # 3D plot
+    ax2.plot(x1, v2, zs=1, zdir='y')
+    ax2.plot(x1, v3, zs=2, zdir='y')