Emulator
How to start a new instance of emulator
Flow Javascript Testing Framework exposes emulator singleton allowing you to start and stop an emulator instance programmatically. There are two methods available on it.
emulator.start(port, logging)
Starts emulator on a specified port. Returns Promise.
Arguments
| Name | Type | Optional | Description |
|---|---|---|---|
port | number | ✅ | number representing a port to use for access API. Default: 8080 |
logging | boolean | ✅ | whether log messages from emulator shall be added to the output |
Usage
import { emulator, init } from "flow-js-testing";
describe("test setup", () => {
// Instantiate emulator and path to Cadence files
beforeEach(async () => {
const basePath = path.resolve(__dirname, "../cadence");
const port = 8080;
await init(basePath, { port });
// Start emulator instance on port 8080
await emulator.start(port);
});
});
emulator.stop()
Stops emulator instance. Returns Promise.
Arguments
This method does not expect any arguments.
Usage
import { emulator, init } from "flow-js-testing";
describe("test setup", () => {
// Instantiate emulator and path to Cadence files
beforeEach(async () => {
const basePath = path.resolve(__dirname, "../cadence");
const port = 8080;
await init(basePath, { port });
await emulator.start(port);
});
// Stop emulator, so it could be restarted
afterEach(async () => {
await emulator.stop();
});
});
emulator.setLogging(newState)
Set logging flag on emulator, allowing to temporally enable/disable logging.
Arguments
| Name | Type | Description |
|---|---|---|
newState | boolean | Enable/disable logging |
Usage
import { emulator, init } from "flow-js-testing";
describe("test setup", () => {
// Instantiate emulator and path to Cadence files
beforeEach(async () => {
const basePath = path.resolve(__dirname, "../cadence");
const port = 8080;
await init(basePath, { port });
await emulator.start(port);
});
// Stop emulator, so it could be restarted
afterEach(async () => {
await emulator.stop();
});
test("basic test", async () => {
// Turn on logging from begining
emulator.setLogging(true);
// some asserts and interactions
// Turn off logging for later calls
emulator.setLogging(false);
// more asserts and interactions here
});
});