Add streamplot with broken_streamlines=False test

Includes some style changes as requested by the matplotlib devs.

Author: aragilar

lib/matplotlib/pyplot.py

@@ -2909,14 +2909,16 @@ def streamplot(
         x, y, u, v, density=1, linewidth=None, color=None, cmap=None,
         norm=None, arrowsize=1, arrowstyle='-|>', minlength=0.1,
         transform=None, zorder=None, start_points=None, maxlength=4.0,
-        integration_direction='both', broken_streamlines=True, *, data=None):
+        integration_direction='both', broken_streamlines=True, *,
+        data=None):
     __ret = gca().streamplot(
         x, y, u, v, density=density, linewidth=linewidth, color=color,
         cmap=cmap, norm=norm, arrowsize=arrowsize,
         arrowstyle=arrowstyle, minlength=minlength,
         transform=transform, zorder=zorder, start_points=start_points,
         maxlength=maxlength,
-        integration_direction=integration_direction, broken_streamlines=broken_streamlines,
+        integration_direction=integration_direction,
+        broken_streamlines=broken_streamlines,
         **({"data": data} if data is not None else {}))
     sci(__ret.lines)
     return __ret

lib/matplotlib/streamplot.py

@@ -70,9 +70,10 @@ def streamplot(axes, x, y, u, v, density=1, linewidth=None, color=None,
         Integrate the streamline in forward, backward or both directions.
     data : indexable object, optional
         DATA_PARAMETER_PLACEHOLDER
-    broken_streamlines : If False, forces streamlines to continue until they
+    broken_streamlines : boolean, default: True
+        If False, forces streamlines to continue until they
         leave the plot domain.  If True, they may be terminated if they
-        come too close to another streamline.  Default is True.
+        come too close to another streamline.
 
     Returns
     -------
@@ -482,13 +483,15 @@ def integrate(x0, y0, broken_streamlines=True):
         except InvalidIndexError:
             return None
         if integration_direction in ['both', 'backward']:
-            s, xyt = _integrate_rk12(x0, y0, dmap, backward_time, maxlength, broken_streamlines)
+            s, xyt = _integrate_rk12(x0, y0, dmap, backward_time, maxlength,
+                                     broken_streamlines)
             stotal += s
             xy_traj += xyt[::-1]
 
         if integration_direction in ['both', 'forward']:
             dmap.reset_start_point(x0, y0)
-            s, xyt = _integrate_rk12(x0, y0, dmap, forward_time, maxlength, broken_streamlines)
+            s, xyt = _integrate_rk12(x0, y0, dmap, forward_time, maxlength,
+                                     broken_streamlines)
             stotal += s
             xy_traj += xyt[1:]
 

lib/matplotlib/tests/baseline_images/test_streamplot/streamplot_maxlength_no_broken.png

@@ -77,6 +77,18 @@ def test_maxlength():
     ax.set(xlim=(None, 3.2555988021882305), ylim=(None, 3.078326760195413))
 
 
+@image_comparison(['streamplot_maxlength_no_broken.png'],
+                  remove_text=True, style='mpl20', tol=0.302)
+def test_maxlength_no_broken():
+    x, y, U, V = swirl_velocity_field()
+    ax = plt.figure().subplots()
+    ax.streamplot(x, y, U, V, maxlength=10., start_points=[[0., 1.5]],
+                  linewidth=2, density=2, broken_streamlines=False)
+    assert ax.get_xlim()[-1] == ax.get_ylim()[-1] == 3
+    # Compatibility for old test image
+    ax.set(xlim=(None, 3.2555988021882305), ylim=(None, 3.078326760195413))
+
+
 @image_comparison(['streamplot_direction.png'],
                   remove_text=True, style='mpl20', tol=0.073)
 def test_direction():