obspy.core.util.testing.ImageComparison¶

class ImageComparison(image_path, image_name, reltol=1, adjust_tolerance=True, plt_close_all_enter=True, plt_close_all_exit=True, style=None, no_uploads=False, *args, **kwargs)[source]¶

Bases: obspy.core.util.base.NamedTemporaryFile

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

Note

Baseline images are created using matplotlib version 1.3.1.

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). adjust_tolerance (bool, optional) Adjust the tolerance based on the matplotlib version. Can optionally be turned off to simply compare two images. plt_close_all_enter (bool) Whether to close all open figures when entering context (matplotlib.pyplot.close() with “all” as first argument. plt_close_all_exit (bool) Whether to call matplotlib.pyplot.close() with “all” as first argument (close all figures) or no arguments (close active figure). Has no effect if plt_close=False. style (str) The Matplotlib style to use to generate the figure. When using matplotlib 1.5 or newer, the default will be 'classic' to ensure compatibility with older releases. On older releases, the default will leave the style as is. You may wish to set it to 'default' to enable the new style from Matplotlib 2.0, or some alternate style, which will work back to Matplotlib 1.4.0. no_uploads (bool) If set to True no uploads to imgur are attempted, no matter what (e.g. any options to obspy-runtests that would normally cause an upload attempt). This can be used to forcibly deactivate upload attempts in image tests that are expected to fail.

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. To only keep failed images and the corresponding diff image, additionally set environment variable OBSPY_KEEP_ONLY_FAILED_IMAGES to any value before executing the test.

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

__abstractmethods__	frozenset() -> empty frozenset object
__dict__
__doc__	str(object=’‘) -> str
__module__	str(object=’‘) -> str
closed

Public Methods

close
compare	Run a custom version
detach	Disconnect this buffer from its underlying raw stream and return it.
fileno	Returns underlying file descriptor if one exists.
flush	Flush write buffers, if applicable.
isatty	Return whether this is an ‘interactive’ stream.
read
read1	Read and return up to n bytes, with at most one read() call to the underlying raw stream.
readable	Return whether object was opened for reading.
readinto
readline	Read and return a line from the stream.
readlines	Return a list of lines from the stream.
seek
seekable	Return whether object supports random access.
tell
truncate	Truncate file to size bytes.
writable	Return whether object was opened for writing.
write
writelines

Private Methods

Warning

Private methods are mainly for internal/developer use and their API might change without notice.

_checkClosed
_checkReadable
_checkSeekable
_checkWritable
_copy_tempfiles	Copies created images from tempfiles to a subfolder of baseline images.
_get_final_filenames	Helper function returning the
_upload_images	Uploads images to imgur unless explicitly deactivated with option no_uploads (to speed up tests that are expected to fail).

Special Methods

__dir__	default dir() implementation
__enter__	Set matplotlib defaults.
__exit__	Remove tempfiles and store created images if OBSPY_KEEP_IMAGES
__format__	default object formatter
__init__
__new__	Create and return a new object.
__reduce__	helper for pickle
__reduce_ex__	helper for pickle
__sizeof__	size of object in memory, in bytes
__subclasshook__	Abstract classes can override this to customize issubclass().