diff --git a/skimage/util/tests/test_montage.py b/skimage/util/tests/test_montage.py
index bc5f2176..a25a6ee4 100644
--- a/skimage/util/tests/test_montage.py
+++ b/skimage/util/tests/test_montage.py
@@ -80,5 +80,6 @@ def test_error_ndim():
     arr_error = np.random.randn(1, 2, 3, 4)
     montage2d(arr_error)
 
+
 if __name__ == '__main__':
     np.testing.run_module_suite()
diff --git a/skimage/util/tests/test_shape.py b/skimage/util/tests/test_shape.py
index 33e3b638..8c62a191 100644
--- a/skimage/util/tests/test_shape.py
+++ b/skimage/util/tests/test_shape.py
@@ -140,5 +140,6 @@ def test_view_as_windows_2D():
                                 [13, 14, 15],
                                 [17, 18, 19]]]]))
 
+
 if __name__ == '__main__':
     np.testing.run_module_suite()
diff --git a/skimage/viewer/canvastools/linetool.py b/skimage/viewer/canvastools/linetool.py
index 0b1d3b0c..c32d0ea7 100644
--- a/skimage/viewer/canvastools/linetool.py
+++ b/skimage/viewer/canvastools/linetool.py
@@ -5,7 +5,7 @@ try:
 except ImportError:
     print("Could not import matplotlib -- skimage.viewer not available.")
 
-from .base import CanvasToolBase, ToolHandles
+from skimage.viewer.canvastools.base import CanvasToolBase, ToolHandles
 
 
 __all__ = ['LineTool', 'ThickLineTool']
diff --git a/skimage/viewer/canvastools/painttool.py b/skimage/viewer/canvastools/painttool.py
index b5d67229..0678c460 100644
--- a/skimage/viewer/canvastools/painttool.py
+++ b/skimage/viewer/canvastools/painttool.py
@@ -8,7 +8,7 @@ try:
 except ImportError:
     print("Could not import matplotlib -- skimage.viewer not available.")
 
-from .base import CanvasToolBase
+from skimage.viewer.canvastools.base import CanvasToolBase
 
 
 __all__ = ['PaintTool']