streamly/test

Streamly Tests

Running tests using bin/test.sh

bin/test.sh (path relative to the top level repo dir) can run selected test groups, generate coverage report, pass GHC RTS options when running tests. test.sh runs the tests with restricted memory, see bin/test.sh source for details on the amount of memory used or to change it.

To generate coverage report:

$ bin/test.sh --coverage

To view coverage report, open ./hpc_index.html in browser.

See bin/test.sh --help for more info.

Building and Running Tests using cabal

Build a single test

$ cabal build test:Prelude.Serial

or:

$ cd test; cabal build Prelude.Serial

Build with optimizations:

$ cabal build --flag opt ...

Build all tests

$ cabal build --enable-tests all

or:

$ cd test; cabal build --enable-tests

Or this, note this command does not work as expected when in the "test" dir:

$ cabal build --enable-tests streamly-tests

Build and run

Running all test suites, use any of the following:

$ cabal test all

or:

$ cd test; cabal test

Or this, note this command does not work as expected when in the "test" dir:

$ cabal test streamly-tests

Build and Run a single test suite

To run Prelude.Serial test-suite:

$ cabal run test:Prelude.Serial

or:

$ cd test; cabal run Prelude.Serial

Note you could use cabal test Prelude.Serial but that unfortunately builds all the test suites before running Prelude.Serial.

Writing doctests

• The test named doctest runs all the code snippets in a source module that are written using the >>> markup in haddock. See doctest.hs.
• Make sure you do not enclose your snippets in the @ .. @ markup otherwise they will show up verbatim in the docs and not as ghci styled snippets.
• We use --fast mode of doctest, which means snippets are run as if you are typing those examples from top to bottom in that order in GHCi. Previous snippet's state is available to the next one.
• A haddock section named $setup contains a snippet that is always run before any other. When --fast mode is not used it is run before every snippet.

An example setup section:

-- $setup
-- >>> :m
-- >>> import Control.Monad.IO.Class (MonadIO(..))
-- >>> import Data.Function ((&))

Some tests that may take long can be written as follows. Just assigning the code to a function makes it compile but not run.

>>> :{
main = do
 Stream.drain $ Stream.fromAsync $ foldMap delay [1..10]
 Stream.drain $ Stream.concatFoldableWith Stream.async (map delay [1..10])
 Stream.drain $ Stream.concatMapFoldableWith Stream.async delay [1..10]
 Stream.drain $ Stream.concatForFoldableWith Stream.async [1..10] delay
:}

Running doctests

Run tests for all modules:

$ cabal run doctests --flag doctests

Use verbose mode to debug:

$ cabal run doctests --flag doctests -- --verbose

Run tests only for selected modules:

$ cabal run doctests --flag doctests -- --modules Streamly.Prelude

If it fails with a message that a particular modules is not loaded specify that module as well on the command line.

Naming of test modules

Tests are organized by source modules. For example, for the source module Streamly.Data.Array and Streamly.Internal.Data.Array we have a test module Data.Array. For some modules tests for a source module are broken into multiple modules. For example, for Streamly.Prelude we have Streamly.Prelude.Serial, Streamly.Prelude.Async etc.