QGIS » QGIS Application

Description:
I am trying to programmatically to snap to the nearest segment or segments. I have a layer with two lines (the corresponding SHAPE layer is attached):

1. (0,0) -> (3,3)
2. (1,1) -> (2,2)

These two lines has a common overlap corresponding to the second line.

Code:
I have set up the snapper as follows:

Setup the snap layer.
>>> sl = QgsSnapper.SnapLayer()
>>> sl.mLayer = iface.mapCanvas().currentLayer()
>>> sl.mTolerance = 25
>>> sl.mSnapTo = QgsSnapper.SnapToSegment
>>> sl.mUnitType = QgsTolerance.Pixels

Setup the snapper.
>>> sn = QgsSnapper(iface.mapCanvas().mapSettings())
>>> sn.setSnapLayers([sl])

I want more than one result if available.
>>> sn.setSnapMode = QgsSnapper.SnapWithResultsWithinTolerances

Snap using the center point of the common overlap - that should ensure both lines are detected.
>>> (retval, result) = sn.snapMapPoint(QgsPoint(1.5, 1.5))

The result, where I expect two items, but the following only gives me one.
>>> len(result)
1

According to https://github.com/qgis/QGIS/blob/master/src/core/qgssnapper.cpp#L108 using either QgsSnapper.SnapWithResultsForSamePosition or QgsSnapper.SnapWithResultsWithinTolerances should allow for more results.

What is going wrong for me here?

To reproduce:

1. Open QGIS.
2. Load the attached layer.
3. Paste the above code into the Python console.