Added tests for contour linestyles and negative_linestyles

andrew-fennell · andrew-fennell · commit 294d3db4d5a6 · 2022-06-13T23:28:19.000-05:00
diff --git a/lib/matplotlib/tests/test_contour.py b/lib/matplotlib/tests/test_contour.py
@@ -605,3 +605,80 @@ def test_subfigure_clabel():
         CS = ax.contour(X, Y, Z)
         ax.clabel(CS, inline=True, fontsize=10)
         ax.set_title("Simplest default with labels")
+
+
+@pytest.mark.parametrize(
+    "style", ['solid', 'dashed', 'dashdot', 'dotted'])
+def test_linestyles(style):
+    delta = 0.025
+    x = np.arange(-3.0, 3.0, delta)
+    y = np.arange(-2.0, 2.0, delta)
+    X, Y = np.meshgrid(x, y)
+    Z1 = np.exp(-X**2 - Y**2)
+    Z2 = np.exp(-(X - 1)**2 - (Y - 1)**2)
+    Z = (Z1 - Z2) * 2
+
+    # Positive contour defaults to solid
+    fig1, ax1 = plt.subplots()
+    CS1 = ax1.contour(X, Y, Z, 6, colors='k')
+    ax1.clabel(CS1, fontsize=9, inline=True)
+    ax1.set_title('Single color - positive contours solid (default)')
+    assert CS1.linestyles is None  # default
+
+    # Change linestyles using linestyles kwarg
+    fig2, ax2 = plt.subplots()
+    CS2 = ax2.contour(X, Y, Z, 6, colors='k', linestyles=style)
+    ax2.clabel(CS2, fontsize=9, inline=True)
+    ax2.set_title(f'Single color - positive contours {style}')
+    assert CS2.linestyles == style
+
+    # Ensure linestyles do not change when negative_linestyles is defined
+    fig3, ax3 = plt.subplots()
+    CS3 = ax3.contour(X, Y, Z, 6, colors='k', linestyles=style,
+                      negative_linestyles='dashdot')
+    ax3.clabel(CS3, fontsize=9, inline=True)
+    ax3.set_title(f'Single color - positive contours {style}')
+    assert CS3.linestyles == style
+
+
+@pytest.mark.parametrize(
+    "style", ['solid', 'dashed', 'dashdot', 'dotted'])
+def test_negative_linestyles(style):
+    delta = 0.025
+    x = np.arange(-3.0, 3.0, delta)
+    y = np.arange(-2.0, 2.0, delta)
+    X, Y = np.meshgrid(x, y)
+    Z1 = np.exp(-X**2 - Y**2)
+    Z2 = np.exp(-(X - 1)**2 - (Y - 1)**2)
+    Z = (Z1 - Z2) * 2
+
+    # Negative contour defaults to dashed
+    fig1, ax1 = plt.subplots()
+    CS1 = ax1.contour(X, Y, Z, 6, colors='k')
+    ax1.clabel(CS1, fontsize=9, inline=True)
+    ax1.set_title('Single color - negative contours dashed (default)')
+    assert CS1.negative_linestyles == 'dashed'  # default
+
+    # Change negative_linestyles using rcParams
+    plt.rcParams['contour.negative_linestyle'] = style
+    fig2, ax2 = plt.subplots()
+    CS2 = ax2.contour(X, Y, Z, 6, colors='k')
+    ax2.clabel(CS2, fontsize=9, inline=True)
+    ax2.set_title(f'Single color - negative contours {style}'
+                   '(using rcParams)')
+    assert CS2.negative_linestyles == style
+
+    # Change negative_linestyles using negative_linestyles kwarg
+    fig3, ax3 = plt.subplots()
+    CS3 = ax3.contour(X, Y, Z, 6, colors='k', negative_linestyles=style)
+    ax3.clabel(CS3, fontsize=9, inline=True)
+    ax3.set_title(f'Single color - negative contours {style}')
+    assert CS3.negative_linestyles == style
+
+    # Ensure negative_linestyles do not change when linestyles is defined
+    fig4, ax4 = plt.subplots()
+    CS4 = ax4.contour(X, Y, Z, 6, colors='k', linestyles='dashdot',
+                      negative_linestyles=style)
+    ax4.clabel(CS4, fontsize=9, inline=True)
+    ax4.set_title(f'Single color - negative contours {style}')
+    assert CS4.negative_linestyles == style
