Jest Helpers

In order to simplify the process even further we've created several Jest-based methods, which will help you to catch thrown errors and ensure your code works as intended.

shallPass(ix)

Ensure transaction did not throw and was sealed.

Arguments

Name	Type	Description
ix	Interaction	interaction, either in form of a Promise or function

Returns

Type	Description
ResponseObject	Transaction result

Usage

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import path from "path"

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import {

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init,

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emulator,

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shallPass,

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sendTransaction,

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getAccountAddress,

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} from "@onflow/flow-js-testing"

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// We need to set timeout for a higher number, because some transactions might take up some time

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jest.setTimeout(10000)

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describe("interactions - sendTransaction", () => {

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// Instantiate emulator and path to Cadence files

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beforeEach(async () => {

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const basePath = path.resolve(__dirname, "./cadence")

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await init(basePath)

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return emulator.start()

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})

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// Stop emulator, so it could be restarted

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afterEach(async () => {

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return emulator.stop()

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})

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test("basic transaction", async () => {

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const code = `

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transaction(message: String){

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prepare(singer: &Account){

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log(message)

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}

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}

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`

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const Alice = await getAccountAddress("Alice")

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const signers = [Alice]

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const args = ["Hello, Cadence"]

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const [txResult, error] = await shallPass(

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sendTransaction({

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code,

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signers,

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args,

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})

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)

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// Transaction result will hold status, events and error message

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console.log(txResult, error)

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})

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})

shallRevert(ix, message)

Ensure interaction throws an error. Can test for specific error messages or catch any error message if message is not provided. Returns Promise, which contains result, when resolved.

Arguments

Name	Type	Description
ix	Interaction	transaction, either in form of a Promise or function
message (optional)	string or RegExp	expected error message provided as either a string equality or regular expression to match, matches any error by default

Returns

Type	Description
ResponseObject	Transaction result

Usage

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import path from "path"

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import {

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init,

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emulator,

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shallPass,

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sendTransaction,

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getAccountAddress,

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} from "js-testing-framework"

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// We need to set timeout for a higher number, cause some interactions might need more time

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jest.setTimeout(10000)

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describe("interactions - sendTransaction", () => {

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// Instantiate emulator and path to Cadence files

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beforeEach(async () => {

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const basePath = path.resolve(__dirname, "./cadence")

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await init(basePath)

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return emulator.start()

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})

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// Stop emulator, so it could be restarted

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afterEach(async () => {

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return emulator.stop()

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})

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test("basic transaction", async () => {

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const code = `

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transaction(message: String){

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prepare(singer: &Account){

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panic("You shall not pass!")

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}

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}

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`

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const Alice = await getAccountAddress("Alice")

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const signers = [Alice]

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const args = ["Hello, Cadence"]

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const [txResult, error] = await shallRevert(

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sendTransaction({

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code,

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signers,

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args,

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})

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)

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// Transaction result will hold status, events and error message

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console.log(txResult, error)

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})

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})

shallResolve(ix)

Ensure interaction resolves without throwing errors.

Arguments

Name	Type	Description
ix	Interaction	interaction, either in form of a Promise or function

Returns

Type	Description
ResponseObject	Transaction result

Usage

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import path from "path"

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import {init, emulator, shallPass, executeScript} from "js-testing-framework"

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// We need to set timeout for a higher number, cause some interactions might need more time

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jest.setTimeout(10000)

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describe("interactions - sendTransaction", () => {

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// Instantiate emulator and path to Cadence files

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beforeEach(async () => {

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const basePath = path.resolve(__dirname, "./cadence")

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await init(basePath)

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return emulator.start()

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})

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// Stop emulator, so it could be restarted

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afterEach(async () => {

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return emulator.stop()

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})

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test("basic script", async () => {

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const code = `

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access(all) fun main():Int{

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return 42

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}

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`

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const [result, error] = await shallResolve(

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executeScript({

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code,

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})

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)

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expect(result).toBe(42)

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expect(error).toBe(null)

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})

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})

shallHavePath(account, path)

Asserts that the given account has the given path enabled.

Arguments

Name	Type	Description
account	string	The address or name of the account to check for the path.
path	string	The path to check for.

Returns

Type	Description
Promise<void>	A Promise that resolves when the assertion is complete, or rejects with an error if it fails.

Usage

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import path from "path"

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import {init, emulator, shallPass, executeScript} from "js-testing-framework"

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// We need to set timeout for a higher number, cause some interactions might need more time

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jest.setTimeout(10000)

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describe("interactions - sendTransaction", () => {

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// Instantiate emulator and path to Cadence files

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beforeEach(async () => {

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const basePath = path.resolve(__dirname, "./cadence")

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await init(basePath)

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return emulator.start()

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})

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// Stop emulator, so it could be restarted

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afterEach(async () => {

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return emulator.stop()

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})

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describe("check path with Jest helper", () => {

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test("pass account address", async () => {

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const Alice = await getAccountAddress("Alice")

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await shallHavePath(Alice, "/storage/flowTokenVault")

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})

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test("pass account name", async () => {

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await shallHavePath("Alice", "/storage/flowTokenVault")

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})

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})

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})

shallHaveStorageValue(account, params)

Asserts that the given account has the expected storage value at the given path.

Arguments

Name	Type	Description
account	string	The address or name of the account to check for the storage value.
params	{pathName: string, key?: string, expect: any}	An object containing the path name, optional key, and expected value of the storage at the given path.
params.pathName	string	The path of the storage value to retrieve.
params.key	string (optional)	The key of the value to retrieve from the storage at the given path, if applicable.
expect	any	The expected value of the storage at the given path and key (if applicable).

Returns

Type	Description
Promise<void>	A Promise that resolves when the assertion is complete, or rejects with an error if it fails.