Assert

Kex ships a minimal RSpec-style testing DSL: describe, it, before, after, and assertion helpers. These are always in scope — no import needed.

A test file typically looks like:

Run with: kex my_test.kex

Output uses ✓ / ✗ markers and nests by describe depth.

function `describe`

describe(label: String, block: Block<Void>) -> Void

Groups related test cases under a label. Calls the block immediately. describe blocks may be nested. This is a foul function — it prints output.

Parameters

label
block

Examples

describe "String" do
  describe "count" do
    it "returns character count" do
      assert("hello".count == 5)
    end
  end
end

function `it`

it(label: String, block: Block<Void>) -> Void

Defines a single test case. The block is run and any exception thrown inside it (typically a failed assert) marks the test failed without aborting the rest of the suite. This is a foul function — it prints output.

Parameters

label
block

Examples

it "returns true for even numbers" do
  assert(2.even?)
  assert(!3.even?)
end

function `before`

before : Block<Void> -> Void
before : Atom -> Block<Void> -> Void

Registers setup for the current group. before { ... } and before(:each) { ... } run before every test; before(:all) { ... } runs once before the group's tests, following RSpec's scope convention.

function `after`

after : Block<Void> -> Void
after : Atom -> Block<Void> -> Void

Registers cleanup for the current group. after { ... } defaults to :each; after(:all) { ... } runs once when the group finishes. Cleanup is unconditional, and inner per-test hooks run before outer hooks.

function `assert`

assert : Bool -> Bool
assert(value: Bool, message: String) -> Bool

Throws a runtime error if value is falsy, failing the enclosing it. The optional message is included in the failure output.

Parameters

value
message: (optional)

Examples

assert(42 == 42)
assert("hello".count == 5, "count should be 5")

module `Assert`

Focused assertions are ordinary Kex stdlib functions layered on the primitive assert, so adding another helper does not require compiler or runtime work.