Testing

Quill has first-class support for testing. No frameworks to install, no configuration to write. Just use test and expect.

Test blocks

A test block groups related assertions under a descriptive name:

test "basic math":
  expect 2 + 2 is 4
  expect 10 - 3 is 7
  expect 3 * 4 is 12

When you run this, you will see:

  ✓ basic math

1 passed, 0 failed

If a test fails:

  ✗ basic math: Expected (2 + 2) === 5 to be true

0 passed, 1 failed

The expect keyword

expect takes an expression that should evaluate to true. If the expression is false, the test fails with an error message.

-- Equality
expect name is "Alice"

-- Comparisons
expect age is greater than 18
expect count is less than 100

-- Membership
expect colors contains "red"

-- Function results
expect length("hello") is 5
expect upper("hello") is "HELLO"

Testing functions

Define your functions, then write tests for them:

to add a b:
  give back a + b

to multiply a b:
  give back a * b

to isEven n:
  give back n % 2 is 0

test "addition":
  expect add(2, 3) is 5
  expect add(-1, 1) is 0
  expect add(0, 0) is 0

test "multiplication":
  expect multiply(3, 4) is 12
  expect multiply(0, 100) is 0
  expect multiply(-2, 3) is -6

test "even numbers":
  expect isEven(4)
  expect not isEven(3)

Running tests

Run your test file just like any Quill program:

quill run tests.quill

Or use the dedicated test command that only runs test blocks:

quill test tests.quill

Example output:

  ✓ addition
  ✓ multiplication
  ✓ even numbers

3 passed, 0 failed

Best practices

• Give each test a descriptive name that explains what it tests
• Keep tests small and focused -- one concept per test block
• Test edge cases: zero, negative numbers, empty strings, empty lists
• Place test files alongside your code with a _test suffix (e.g., math_test.quill)

A complete test file

-- string_test.quill

test "upper and lower":
  expect upper("hello") is "HELLO"
  expect lower("HELLO") is "hello"

test "trim":
  expect trim("  hi  ") is "hi"

test "startsWith and endsWith":
  expect startsWith("hello", "he")
  expect endsWith("hello", "lo")
  expect not startsWith("hello", "lo")

test "replace":
  expect replace_text("hello world", "world", "Quill") is "hello Quill"

test "split and join":
  words are split("a,b,c", ",")
  expect length(words) is 3
  expect join(words, "-") is "a-b-c"