Inline Tests

Write expect() assertions in your code and see pass/fail results inline.

Write expect() assertions directly in your code and ParrotJS reports pass/fail right at the assertion line — no test framework, no config, no test runner.

Writing Assertions

const sum = add(5, 7);
expect(sum).toBe(12);  // ✓ pass
expect(sum).toBe(13);  // ✗ expected 12 to be 13

Passing assertions show a green ✓ at the line; failures show ✗ with the actual-vs-expected mismatch.

Supported Matchers

Matcher	Checks
`toBe(value)`	Strict equality (`===`)
`toEqual(value)`	Deep equality
`toStrictEqual(value)`	Deep equality with strict type/undefined handling
`toContain(item)`	Array/string membership
`toThrow()`	That the call throws
`toBeTruthy()`	Truthy value
`toBeFalsy()`	Falsy value
`toBeNull()`	`null`
`toBeUndefined()`	`undefined`
`toBeGreaterThan(n)`	Value is greater than `n`
`toBeGreaterThanOrEqual(n)`	Value is greater than or equal to `n`
`.not`	Negates any of the above

More Examples

const items = [1, 2, 3];
expect(items).toContain(3);      // ✓ pass
expect(items).toContain(99);     // ✗ expected [1,2,3] to contain 99
expect(items).not.toContain(99); // ✓ pass

const risky = () => { throw new Error('boom'); };
expect(risky).toThrow();         // ✓ pass

How Results Display

Inline — passing assertions show a green ✓ at the line; failures show ✗ with the actual-vs-expected mismatch.
Status bar — at-a-glance pass/fail counts (e.g. 4 ✓ 2 ✗).
Output panel — each result is logged with its file.

Free vs PRO

Inline pass/fail assertion decorations and the status bar counts are available on the free tier.

The test results panel (a dedicated summary view of all assertions) is a PRO feature — see Free vs PRO.