web-platform-tests Harness

This harness is designed for running the W3C web-platform-tests testsuite_.

The code hasn't been merged to master yet, but when it is the documentation below might be quite relevant.

Installation

wptrunner is expected to be installed into a virtualenv using pip. For development, it can be installed using the -e option:

pip install -e ./

Running the Tests

After installation the command wptrunner should be avaliable to run the tests. This takes two arguments; the path to the metadata directory containing expectation files (see below) and a MANIFEST.json file (see the web-platform-tests documentation for isntructions on generating this file), and the path to the web-platform-tests checkout:

wptrunner /path/to/metadata /path/to/tests

There are also a variety of other options available; use --help to list them.

Expectation Data

wptrunner is designed to be used in an environment where it is not just necessary to know which tests passed, but to compare the results between runs. For this reason it is possible to store the results of a previous run in a set of ini-like "expectation files". This format is documented below. To generate the expectation files use wptrunner with the --log-raw=/path/to/log/file option. This can then be used as input to the wptupdate tool.

Expectation File Format

Metadat about tests, notably including their expected results, is stored in a modified ini-like format that is designed to be human editable, but also to be machine updatable.

Each test file that requires metadata to be specified (because it has a non-default expectation or because it is disabled, for example) has a corresponding expectation file in the metadata directory. For example a test file html/test1.html containing a failing test would have an expectation file called html/test1.html.ini in the metadata directory.

An example of an expectation file is:

example_default_key: example_value

[filename.html]
  type: testharness

  [subtest1]
    expected: FAIL

  [subtest2]
    expected:
      if platform == 'win': TIMEOUT
      if platform == 'osx': ERROR
      FAIL

[filename.html?query=something]
  type: testharness
  disabled: bug12345

The file consists of two elements, key-value pairs and sections.

Sections are delimited by headings enclosed in square brackets. Any closing square bracket in the heading itself my be escaped with a backslash. Each section may then contain any number of key-value pairs followed by any number of subsections. So that it is clear which data belongs to each section without the use of end-section markers, the data for each section (i.e. the key-value pairs and subsections) must be indented using spaces. Indentation need only be consistent, but using two spaces per level is recommended.

In a test expectation file, each resource provided by the file has a single section, with the section heading being the part after the last / in the test url. Tests that have subsections may have subsections for those subtests in which the heading is the name of the subtest.

Simple key-value pairs are of the form:

key: value

Note that unlike ini files, only : is a valid seperator; = will not work as expected. Key-value pairs may also have conditional values of the form:

key:
  if condition1: value1
  if condition2: value2
  default

In this case each conditional is evaluated in turn and the value is that on the right hand side of the first matching conditional. In the case that no condition matches, the unconditional default is used. If no condition matches and no default is provided it is equivalent to the key not being present. Conditionals use a simple python-like expression language e.g.:

if debug and (platform == "linux" or platform == "osx"): FAIL

For test expectations the avaliable variables are those in the run_info which for desktop are version, os, bits, processor, debug and product.

Key-value pairs specified at the top level of the file before any sections are special as they provide defaults for the rest of the file e.g.:

key1: value1

[section 1]
  key2: value2

[section 2]
  key1: value3

In this case, inside section 1, key1 would have the value value1 and key2 the value value2 whereas in section 2 key1 would have the value value3 and key2 would be undefined.

The web-platform-test harness knows about several keys:

expected

Must evaluate to a possible test status indicating the expected result of the test. The implicit default is PASS or OK when the field isn't present.

disabled

Any value indicates that the test is disabled.

type

The test type e.g. testharness or reftest.

reftype

The type of comparison for reftests; either == or !=.

refurl

The reference url for reftests.

_testsuite: https://github.com/w3c/web-platform-tests