Filtering tests by tags

Avocado allows tests to be given tags, which can be used to create test categories. With tags set, users can select a subset of the tests found by the test resolver.

Usually, listing and executing tests with the Avocado test runner would reveal all three tests:

$ avocado list examples/tests/tags.py
avocado-instrumented examples/tests/tags.py:FastTest.test_fast
avocado-instrumented examples/tests/tags.py:FastTest.test_fast_other
avocado-instrumented examples/tests/tags.py:SlowTest.test_slow
avocado-instrumented examples/tests/tags.py:SlowUnsafeTest.test_slow_unsafe
avocado-instrumented examples/tests/tags.py:SafeTest.test_safe
avocado-instrumented examples/tests/tags.py:SafeX86Test.test_safe_x86
avocado-instrumented examples/tests/tags.py:NoTagsTest.test_no_tags
avocado-instrumented examples/tests/tags.py:SafeAarch64Test.test_safe_aarch64

If you want to list or run only the network based tests, you can do so by requesting only tests that are tagged with net:

$ avocado list examples/tests/tags.py --filter-by-tags=net
avocado-instrumented examples/tests/tags.py:FastTest.test_fast
avocado-instrumented examples/tests/tags.py:FastTest.test_fast_other

Now, suppose you’re not in an environment where you’re comfortable running a test that will write to your raw disk devices (such as your development workstation). You know that some tests are tagged with safe while others are tagged with unsafe. To only select the “safe” tests you can run:

$ avocado list examples/tests/tags.py --filter-by-tags=safe
avocado-instrumented examples/tests/tags.py:SafeTest.test_safe
avocado-instrumented examples/tests/tags.py:SafeX86Test.test_safe_x86
avocado-instrumented examples/tests/tags.py:SafeAarch64Test.test_safe_aarch64

But you could also say that you do not want the “unsafe” tests (note the minus sign before the tag):

$ avocado list examples/tests/tags.py --filter-by-tags=-unsafe
avocado-instrumented examples/tests/tags.py:FastTest.test_fast
avocado-instrumented examples/tests/tags.py:FastTest.test_fast_other
avocado-instrumented examples/tests/tags.py:SlowTest.test_slow
avocado-instrumented examples/tests/tags.py:SafeTest.test_safe
avocado-instrumented examples/tests/tags.py:SafeX86Test.test_safe_x86
avocado-instrumented examples/tests/tags.py:SafeAarch64Test.test_safe_aarch64

Tip

The - sign may cause issues with some shells. One know error condition is to use spaces between --filter-by-tags and the negated tag, that is, --filter-by-tags -unsafe will most likely not work. To be on the safe side, use --filter-by-tags=-tag.

If you require tests to be tagged with multiple tags, just add them separate by commas. Example:

$ avocado list examples/tests/tags.py --filter-by-tags=disk,slow,unsafe
avocado-instrumented examples/tests/tags.py:SlowUnsafeTest.test_slow_unsafe

If no test contains all tags given on a single --filter-by-tags parameter, no test will be included:

$ avocado list examples/tests/tags.py --filter-by-tags=disk,slow,safe | wc -l
0

Multiple tags (AND vs OR)

While multiple tags in a single option will require tests with all the given tags (effectively a logical AND operation), it’s also possible to use multiple --filter-by-tags (effectively a logical OR operation).

For instance To include all tests that have the disk tag and all tests that have the net tag, you can run:

$ avocado list examples/tests/tags.py --filter-by-tags=disk --filter-by-tags=net
avocado-instrumented examples/tests/tags.py:FastTest.test_fast
avocado-instrumented examples/tests/tags.py:FastTest.test_fast_other
avocado-instrumented examples/tests/tags.py:SlowTest.test_slow
avocado-instrumented examples/tests/tags.py:SlowUnsafeTest.test_slow_unsafe

Including tests without tags

The normal behavior when using --filter-by-tags is to require the given tags on all tests. In some situations, though, it may be desirable to include tests that have no tags set.

For instance, you may want to include tests of certain types that do not have support for tags (such as executable tests) or tests that have not (yet) received tags. Consider this command:

$ avocado list examples/tests/tags.py /bin/true --filter-by-tags=disk
avocado-instrumented examples/tests/tags.py:SlowTest.test_slow
avocado-instrumented examples/tests/tags.py:SlowUnsafeTest.test_slow_unsafe

Since it requires the disk tag, only one test was returned. By using the --filter-by-tags-include-empty option, you can force the inclusion of tests without tags:

$ avocado list examples/tests/tags.py /bin/true --filter-by-tags=disk --filter-by-tags-include-empty
avocado-instrumented examples/tests/tags.py:SlowTest.test_slow
avocado-instrumented examples/tests/tags.py:SlowUnsafeTest.test_slow_unsafe
avocado-instrumented examples/tests/tags.py:NoTagsTest.test_no_tags
exec-test            /bin/true

Using further categorization with keys and values

All the examples given so far are limited to “flat” tags. Sometimes, it’s helpful to categorize tests with extra context. For instance, if you have tests that are sensitive to the platform endianness, you may way to categorize them by endianness, while at the same time, specifying the exact type of endianness that is required.

For instance, your tags can now have a key and value pair, like: endianess:little or endianess:big.

To list tests without any type of filtering would give you:

$ avocado list byteorder.py
avocado-instrumented byteorder.py:ByteOrder.test_le
avocado-instrumented byteorder.py:ByteOrder.test_be
avocado-instrumented byteorder.py:Generic.test

To list tests that are somehow related to endianness, you can use:

$ avocado list byteorder.py --filter-by-tags endianness
avocado-instrumented byteorder.py:ByteOrder.test_le
avocado-instrumented byteorder.py:ByteOrder.test_be

And to be even more specific, you can use:

$ avocado list byteorder.py --filter-by-tags endianness:big
avocado-instrumented byteorder.py:ByteOrder.test_be

A “negated” form is also available to filter out tests that do not have a given value. To filter out tests that have an endianness set, but are not big endian you can use:

$ avocado list byteorder.py --filter-by-tags endianness:-big
avocado-instrumented byteorder.py:ByteOrder.test_le

Now, suppose you intend to run tests on a little endian platform, but you’d still want to include tests that are generic enough to run on either little or big endian (but not tests that are specific to other types of endianness), you could use:

$ avocado list byteorder.py --filter-by-tags endianness:big --filter-by-tags-include-empty-key
avocado-instrumented byteorder.py:ByteOrder.test_be
avocado-instrumented byteorder.py:Generic.test