jest_typescript_integration

Jest TypeScript Integration Example

Detailed documentation on the Jest integration is available in the main Jazzer.js documentation.

Quickstart

To use the Jest integration install the @jazzer.js/jest-runner and ts-jest packages then configure jest-runner as a dedicated test runner in package.json or jest.config.{ts|js}.

The example below shows how to configure the Jazzer.js Jest integration in combination with the normal Jest runner.

{
	"jest": {
		"projects": [
			{
				"displayName": "Jest",
				"preset": "ts-jest"
			},
			{
				"displayName": {
					"name": "Jazzer.js",
					"color": "cyan"
				},
				"preset": "ts-jest",
				"testRunner": "@jazzer.js/jest-runner",
				"testEnvironment": "node",
				"testMatch": ["<rootDir>/*.fuzz.[jt]s"]
			}
		],
		"coveragePathIgnorePatterns": ["/node_modules/", "/dist/"],
		"modulePathIgnorePatterns": ["/node_modules", "/dist/"]
	}
}

Further configuration can be specified in .jazzerjsrc, like in any other project, in the following format:

{
	"includes": ["*"],
	"excludes": ["node_modules"],
    [...]
}

Write a Jest fuzz test like:

// file: jazzerjs.fuzz.ts
import "@jazzer.js/jest-runner";
describe("My describe", () => {
	it.fuzz("My fuzz test", (data: Buffer) => {
		target.fuzzMe(data);
	});
});

Note: the import statement extends jest's It interface to include the fuzz property and is necessary for TypeScript to compile the test file.