Testing

Tests are Functions marked @Test, anywhere in a package, beside the code they test, where they see its file’s Private names. fb test builds them and runs them, in parallel, in one process. fb build and fb run leave them out.

@Test and std.test

A test takes nothing, and returns nothing or throws. Import std.test brings in:

A panic, an Assert that fails, or an error the test throws fails it too.

Import std.core
Import std.test

Public Class OutOfStock Extends Error
End Class

Function Take(stock: Int, count: Int): Int Throws OutOfStock
    If count > stock Then Throw OutOfStock("only {stock} left")
    Return stock - count
End Function

@Test
Function TakingLeavesTheRest() Throws OutOfStock
    Expect(Try Take(5, 2) == 3)
    Expect(Try Take(2, 2) == 0)
End Function

@Test
Function TakingTooManyThrows()
    Local error = ExpectThrows<OutOfStock>(Take(1, 2))
    Expect(error?.Message == "only 1 left")
End Function

     Running 2 tests
test main.TakingLeavesTheRest ... ok
test main.TakingTooManyThrows ... ok

test result: ok. 2 passed; 0 failed; 0 skipped; 0 filtered out; finished in 0.02s

A failing test

A failed Expect says where, what it tested, and each side’s value:

     Running 1 test
test shop.stock.TakingLeavesTheRest ... FAILED

failures:

---- shop.stock.TakingLeavesTheRest ----
expect failed: Try Take(5, 2) == 4 at stock.fb:14:5
  left: 3
  right: 4

test result: FAILED. 0 passed; 1 failed; 0 skipped; 0 filtered out; finished in 0.02s

fb exits with 1 when a test fails.

A test that panics doesn’t stop the others: fb starts the process again and runs the ones left. In a debug build, the memory a test leaks is reported with it.

A package’s tests/ folder

The .fb files of a package’s tests/ folder are tests that use the package from outside, as another package would: through its Public names only. The package builds without them.

Doc tests

The examples under # Examples in doc comments are tests too, each named after what it documents, as shop.prices.Price (example). fb test std runs the standard library’s.

Choosing tests

fb test --filter <text> runs only the tests whose names have the text in them. A test’s name is its module’s and its own, like shop.stock.TakingTooManyThrows.

Testing in CI runs them on every push.