Test.Tasty.Runners

The main data structure defining a test suite.

It consists of individual test cases and properties, organized in named groups which form a tree-like hierarchy.

There is no generic way to create a test case. Instead, every test provider (tasty-hunit, tasty-smallcheck etc.) provides a function to turn a test case into a TestTree.

Groups can be created using testGroup.

Fold a test tree into a single value.

The fold result type should be a monoid. This is used to fold multiple results in a test group. In particular, empty groups get folded into mempty.

Apart from pure convenience, this function also does the following useful things:

1. Keeping track of the current options (which may change due to PlusTestOptions nodes)

2. Filtering out the tests which do not match the patterns

Thus, it is preferred to an explicit recursive traversal of the tree.

An algebra for folding a TestTree.

Instead of constructing fresh records, build upon trivialFold instead. This way your code won't break when new nodes/fields are indroduced.

trivialFold can serve as the basis for custom folds. Just override the fields you need.

Here's what it does:

• single tests are mapped to mempty (you probably do want to override that)

• test groups are returned unmodified

• for a resource, an IO action that throws an exception is passed (you want to override this for runners/ingredients that execute tests)

ResourceSpec describes how to acquire a resource (the first field) and how to release it (the second field).

Monoid generated by *>.

Monoid generated by liftA2 (<>)

Starting from GHC 8.6, a similar type is available from Data.Monoid. This type is nevertheless kept for compatibility.

Ingredients make your test suite tasty.

Ingredients represent different actions that you can perform on your test suite. One obvious ingredient that you want to include is one that runs tests and reports the progress and results.

Another standard ingredient is one that simply prints the names of all tests.

Similar to test providers (see IsTest), every ingredient may specify which options it cares about, so that those options are presented to the user if the ingredient is included in the test suite.

An ingredient can choose, typically based on the OptionSet, whether to run. That's what the Maybe is for. The first ingredient that agreed to run does its work, and the remaining ingredients are ignored. Thus, the order in which you arrange the ingredients may matter.

Usually, the ingredient which runs the tests is unconditional and thus should be placed last in the list. Other ingredients usually run only if explicitly requested via an option. Their relative order thus doesn't matter.

That's all you need to know from an (advanced) user perspective. Read on if you want to create a new ingredient.

There are two kinds of ingredients.

The first kind is TestReporter. If the ingredient that agrees to run is a TestReporter, then tasty will automatically launch the tests and pass a StatusMap to the ingredient. All the ingredient needs to do then is to process the test results and probably report them to the user in some way (hence the name).

TestManager is the second kind of ingredient. It is typically used for test management purposes (such as listing the test names), although it can also be used for running tests (but, unlike TestReporter, it has to launch the tests manually if it wants them to be run). It is therefore more general than TestReporter. TestReporter is provided just for convenience.

The function's result should indicate whether all the tests passed.

In the TestManager case, it's up to the ingredient author to decide what the result should be. When no tests are run, the result should probably be True. Sometimes, even if some tests run and fail, it still makes sense to return True.

Time in seconds. Used to measure how long the tests took to run.

Run the first Ingredient that agrees to be run.

If no one accepts the task, return Nothing. This is usually a sign of misconfiguration.

Return the options which are relevant for the given ingredient.

Note that this isn't the same as simply pattern-matching on Ingredient. E.g. options for a TestReporter automatically include NumThreads.

Like ingredientOptions, but folds over multiple ingredients.

Parse the command-line and environment options passed to tasty.

Useful if you need to get the options before defaultMain is called.

Once within the test tree, askOption should be used instead.

The arguments to this function should be the same as for defaultMainWithIngredients. If you don't use any custom ingredients, pass defaultIngredients.

Generate a command line parser from a list of option descriptions, alongside any related warning messages.

The command line parser for the test suite, alongside any related warnings.

Parse the command line arguments and run the tests using the provided ingredient list.

When the tests finish, this function calls exitWith with the exit code that indicates whether any tests have failed. See defaultMain for details.

Current status of a test.

A test result.

Outcome of a test run

Note: this is isomorphic to Maybe FailureReason. You can use the generic-maybe package to exploit that.

If a test failed, FailureReason describes why.

True for a passed test, False for a failed one.

Test progress information.

This may be used by a runner to provide some feedback to the user while a long-running test is executing.

Empty progress

Mapping from test numbers (starting from 0) to their status variables.

This is what an ingredient uses to analyse and display progress, and to detect when tests finish.

Start running the tests (in background, in parallel) and pass control to the callback.

Once the callback returns, stop running the tests.

The number of test running threads is determined by the NumThreads option.

Number of parallel threads to use for running tests.

Note that this is not included in coreOptions. Instead, it's automatically included in the options for any TestReporter ingredient by ingredientOptions, because the way test reporters are handled already involves parallelism. Other ingredients may also choose to include this option.

Exceptions related to dependencies between tests.

All the options relevant for this test suite. This includes the options for the test tree and ingredients, and the core options.

The list of all core options, i.e. the options not specific to any provider or ingredient, but to tasty itself. Currently contains TestPattern and Timeout.

Measure the time taken by an IO action to run.

Force elements of a list (https://ro-che.info/articles/2015-05-28-force-list).

Catch possible exceptions that may arise when evaluating a string. For normal (total) strings, this is a no-op.

This function should be used to display messages generated by the test suite (such as test result descriptions).

See e.g. https://github.com/UnkindPartition/tasty/issues/25.

Install signal handlers so that e.g. the cursor is restored if the test suite is killed by SIGTERM. Upon a signal, a SignalException will be thrown to the thread that has executed this action.

This function is called automatically from the defaultMain* family of functions. You only need to call it explicitly if you call Test.Tasty.Runners.tryIngredients yourself.

This function does nothing when POSIX signals are not supported.

This exception is thrown when the program receives a signal, assuming installSignalHandlers was called.

The CInt field contains the signal number, as in Signal. We don't use that type synonym, however, because it's not available on non-UNIXes.

Get monotonic time.

Warning: This is not the system time, but a monotonically increasing time that facilitates reliable measurement of time differences.