Testing tools#
Iris has various internal convenience functions and utilities available to
support writing tests. Using these makes tests quicker and easier to write, and
also consistent with the rest of Iris (which makes it easier to work with the
code). Most of these conveniences are accessed through the
iris.tests.IrisTest
class, from
which Iris’ test classes then inherit.
Tip
All functions listed on this page are defined within
iris.tests.__init__.py
as methods of
iris.tests.IrisTest_nometa
(which iris.tests.IrisTest
inherits from). They can be accessed within a test using
self.exampleFunction
.
Custom assertions#
iris.tests.IrisTest
supports a variety of custom unittest-style
assertions, such as assertArrayEqual()
,
assertArrayAlmostEqual()
.
Saving results#
Some tests compare the generated output to the expected result contained in a
file. Custom assertions for this include
assertCMLApproxData()
assertCDL()
assertCML()
and
assertTextFile()
. See docstrings for more
information.
Note
Sometimes code changes alter the results expected from a test containing the
above methods. These can be updated by removing the existing result files
and then running the file containing the test with a --create-missing
command line argument, or setting the IRIS_TEST_CREATE_MISSING
environment variable to anything non-zero. This will create the files rather
than erroring, allowing you to commit the updated results.
Context managers#
Capturing exceptions and logging#
iris.tests.IrisTest
includes several context managers that can be used
to make test code tidier and easier to read. These include
assertWarnsRegexp()
and
assertLogs()
.
Temporary files#
It’s also possible to generate temporary files in a concise fashion with
temp_filename()
.
Patching#
patch()
is a wrapper around unittest.patch
that will be automatically cleaned up at the end of the test.
Graphic tests#
As a package capable of generating graphical outputs, Iris has utilities for creating and updating graphical tests - see Adding or Updating Graphics Tests for more information.