Test262-Harness

Test Authoring Quick Start

1. Clone test262 locally:

   git clone https://github.com/tc39/test262.git --depth 1
   cd test262
   
2. Install test262-harness:

   npm install -g test262-harness
   
3. Run some tests!

   test262-harness test/**/*.js
   

Run test262-harness --help for details on the various configuration options.

Options

Option Name	Description	Required	Default
-h, --help	Show help & examples	n/a	n/a
-v, --version	Print the current version of test262-harness	n/a	n/a
--hostType	Type of host to run tests in. See eshost's supported hosts for available options.	No	node
--hostPath	Path to the host executable.	Yes, if hostType is specified	process.execPath
--hostArgs	Any additional arguments to pass to the host when invoking it (eg. --harmony, --es6all, etc).	No	n/a
-t, --threads	Run this many tests in parallel. Note that the browser runners don't work great with t > 1.	No	1
-r, --reporter	Format of data written to standard output. Currently either json or simple.	No	simple
--features	Comma-separated list of features to filter for. Example: --features="BigInt,Atomics".	No	n/a
--reporter-keys	Comma-separated list of keys to include in output of json reporter.	No	n/a
--test262Dir	Root test262 directory and is used to locate the includes directory.	No	Relative to test files
--includesDir	Includes directory.	No	Inferred from test262Dir or else detected by walking upward from the first test found.
--tempDir	Directory that eshost will create its temp files in (does not affect location of files created by --saveCompiledTests and --saveOnlyFailed	No	OS Temp Dir
--prelude	Path to a file to include before every test (useful for testing polyfills for example); supports multiple --prelude parameters	No	n/a
--timeout	Set a custom test timeout in milliseconds	No	10000
--transformer	Path to module which exports a code transformer function	No	n/a
--preprocessor	Path to module which exports a map function that operates on each Test262Test object before it executed.	No	n/a
--acceptVersion	Execute tests from a version of Test262 that differs from the versions supported by this utility. This may cause the utility to report invalid test results.	No	Inferred from test262Dir/package.json
--saveCompiledTests	Write the compiled version of path/to/test.js as path/to/test.js.<hostType>.<default|strict>.<pass|fail> so that it can be easily re-run under that host. Run test262-harness --help for examples.	No	n/a
--saveOnlyFailed	Only save the compiled version of the test if it failed, to help easily repro failed tests (implies --saveCompiledTests).	No	n/a

Preprocessor

The --preprocessor feature allows a module that exports a map function that operates on each Test262Test object (ie. the object emitted by Test262-Stream) before their execution.

test.result = Result Object

In some cases, a preprocessor may want to signal to Test262-Harness that a certain result has already been reached, and that it must not further evaluate the test. To create this signal, the preprocessor creates a result property on the Test262Test object, which will indicate to Test262-Harness that it must not evaluate the test, but instead return the value of the result property as though the test had been executed. For example, a preprocessor may attempt to transpile the value of test.contents—which may fail! In the case of failure, the preprocessor can create a result property whose value is a Result Object. This will skip the code evaluation and report the given result object.

module.exports = function(test) {
  try {
    test.contents = babel.transform(test.contents, options).code;
  } catch (error) {
    test.result = {
      stderr: `${error.name}: ${error.message}\n`,
      stdout: '',
      error
    };
  }

  return test;
};