obspy.core.util.testing.ImageComparison

class ImageComparison(image_path, image_name, reltol=1, *args, **kwargs)[source]

Bases: obspy.core.util.base.NamedTemporaryFile

Handles the comparison against a baseline image in an image test.

Parameters:
  • image_path (str) Path to directory where the baseline image is located
  • image_name (str) Filename (with suffix, without directory path) of the baseline image
  • reltol (float (optional)) Multiplier that is applied to the default tolerance value (i.e. 10 means a 10 times harder to pass test tolerance).

The class should be used with Python’s “with” statement. When setting up, the matplotlib rcdefaults are set to ensure consistent image testing. After the plotting is completed, the ImageComparison.compare() method is called automatically at the end of the “with” block, comparing against the previously specified baseline image. This raises an exception (if the test fails) with the message string from matplotlib.testing.compare.compare_images(). Afterwards all temporary files are deleted automatically.

Note

If images created during the testrun should be kept after the test, set environment variable OBSPY_KEEP_IMAGES to any value before executing the test (e.g. with $ OBSPY_KEEP_IMAGES= obspy-runtests or $ OBSPY_KEEP_IMAGES= python test_sometest.py). For obspy-runtests the option “keep-images” can also be used instead of setting an environment variable. Created images and diffs for failing tests are then stored in a subfolder “testrun” under the baseline image’s directory.

Example

>>> from obspy import read
>>> with ImageComparison("/my/baseline/folder", 'plot.png') as ic:
...     st = read()  
...     st.plot(outfile=ic.name)  
...     # image is compared against baseline image automatically

Attributes

__dict__
__doc__ str(object=’‘) -> string
__module__ str(object=’‘) -> string
__weakref__ list of weak references to the object (if defined)

Public Methods

compare Run matplotlib.testing.compare.compare_images() and raise an

Private Methods

_copy_tempfiles Copies created images from tempfiles to a subfolder of baseline images.

Special Methods

__enter__ Set matplotlib defaults.
__exit__ Remove tempfiles and store created images if OBSPY_KEEP_IMAGES
__getattr__
__init__

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