0.0.2 • Public • Published


This package allows you to write unit tests for Clarity smart contracts in the Clarity language itself, as opposed to TypeScript. clarunit will automatically detect test files and test functions.

An example Clarinet-sdk project using clarunit can be found in the example folder.


  1. Install package @stacks/clarunit using your favourite package manager. (Be sure to pin the version!)
  2. Create a test file in your existing tests folder, you can use any name but using clarunit.test.ts is recommended.
  3. Add the following to the newly created file:
    import { clarunit } from "clarunit";
  4. Run your tests per usual using npm test or yarn test.

clarunit takes configuration from Clarinet via Clarinet.toml. It automatically detects all instantiated test contracts.

Unit testing

Adding tests

To write unit tests, follow these steps:

  1. Create a new Clarity contract in the ./tests folder. It can have any name but it should end in _test.clar. Files that do not follow this convention are ignored. (For example: my-contract_test.clar will be included and my-contract.clar will not.)
  2. Add the new Clarity contract to Clarinet.toml.
  3. Write unit tests as public functions, the function name must start with test-.

Writing tests

Unit test functions should be public without parameters. If they return an ok response of any kind, the test is considered to have passed whereas an err indicates a failure. The failure value is printed so it can be used to provide a helpful message. The body of the unit test is written like one would usually write Clarity, using try! and unwrap! and so on as needed.


(define-public (test-my-feature)
		(unwrap! (contract-call? .some-project-contract my-feature) (err "Calling my-feature failed"))
		(ok true)

Prepare function

Sometimes you need to run some preparation logic that is common to all or multiple unit tests. If the script detects a function called prepare, it will be invoked before calling the unit test function itself. The prepare function should return an ok, otherwise the test fails.

(define-public (prepare)
		(unwrap! (contract-call? .some-project-contract prepare-something) (err "Preparation failed"))
		(ok true)

(define-public (test-something)
	;; prepare will be executed before running the test.


You can add certain comment annotations before unit test functions to add information or modify behaviour. Annotations are optional.

Annotation Description
@name Give the unit test a name, this text shows up when running unit tests.
@no-prepare Do not call the prepare function before running this unit test.
@prepare Override the default prepare function with another. The function name should follow the tag.
@caller Override the default caller when running this unit test. Either specify an account name or standard principal prefixed by a single tick '.
@mine-blocks-before Mine a number of blocks before running the test. The number of blocks should follow the tag.


(define-public (prepare) (ok "Default prepare function"))

(define-public (custom-prepare) (ok "A custom prepare function"))

;; A test without any annotations
(define-public (test-zero) (ok true))

;; @name A normal test with a name, the prepare function will run before.
(define-public (test-one) (ok true))

;; @name This test will be executed without running the default prepare function.
;; @no-prepare
(define-public (test-two) (ok true))

;; @name Override the default prepare function, it will run custom-prepare instead.
;; @prepare custom-prepare
(define-public (test-three) (ok true))

;; @name This test will be called with tx-sender set to wallet_1 (from the settings toml file).
;; @caller wallet_1
(define-public (test-four) (ok true))

;; @name This test will be called with tx-sender set to the specified principal.
(define-public (test-five) (ok true))

;; @name Five blocks are mined before this test is executed.
;; @mine-blocks-before 5
(define-public (test-six) (ok true))

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