Something I’ve become accustomed to while coding in Scala is being able to run a subset of tests through SBT. And while the same functionality is possible through Tasty, I found it a little difficult to use through Stack.

Now stack allows you to send through parameters to your testing framework with the following options:

--ta,--test-arguments TEST_ARGS Arguments passed in to the test suite program

So given a full test suite of:

    exits from home screen:       OK
    handles invalid query syntax: OK
    handle valid query:           OK
    handle invalid index:         OK
    handle invalid action:        OK
    go home from search:          OK
    quit from search:             OK
    search without results:       OK

Using plain Tasty, you can use the -p argument to run tests that match a pattern:

-p,--pattern ARG         Select only tests that match pattern

Combining the two options, I can choose to run only the quit from search test with:

stack test --ta '-p "quit from search"'

which results in running only that specific test:

    quit from search: OK

All 1 tests passed (0.00s)

As long as the string you pass to Tasty is specific, you can target tests at different levels (TestGroup, TestCase etc).

For example to only target the CommandParser test group I could use:

stack test --ta '-p "CommandParser"'

which results in running all the tests with the the CommandParser test group:

    matchValue parser should match one of *?^:                  OK
    matchValue parser should not match other chars:             OK
      +++ OK, passed 100 tests.
    matchType parser should match format: "> [*?^]":            OK
    query parser should parse a valid query with matches:       OK
    query parser should parse a valid query with only commands: OK
    query parser should parse all valid queries:                OK
      +++ OK, passed 100 tests.

All 6 tests passed (0.00s)

And to target a specific test case within a Test Group I could use the



For example to run the matchValue parser should not match other chars test within the CommandParser test group, I could use:

stack test --ta '-p "CommandParser/matchValue parser should not match other chars"'

which results in:

    matchValue parser should not match other chars: OK
      +++ OK, passed 100 tests.

All 1 tests passed (0.01s)

While this great, the version of Tasty I’m using (0.11.3) has support for additional patterns:

An optional prefixed bang ! negates the pattern.

If the pattern ends with a slash, it is removed for the purpose of the following description, but it would only find a match with a test group. In other words, foo/ will match a group called foo and any tests underneath it, but will not match a regular test foo.

If the pattern does not contain a slash /, the framework checks for a match against any single component of the path. Otherwise, the pattern is treated as a glob, where:

The wildcard * matches anything within a single path component (i.e. foo but not foo/bar).

Two wildcards ** matches anything (i.e. foo and foo/bar).

Anything else matches exactly that text in the path (i.e. foo would only match a component of the test path called foo (or a substring of that form).

For example, group/*1 matches group/test1 but not group/subgroup/test1, whereas both examples would be matched by group/**1. A leading slash matches the beginning of the test path; for example, /test* matches test1 but not group/test1.

Newer versions of Tasty such as 1.0 onward support even more advanced syntax.

Now that’s pretty neat!