use-plan-well.md

Prevent the incorrect use of t.plan()

t.plan() is useful for ensuring every single assertion is executed, and to catch unexpected flow errors.

t.plan() has a few basic usage rules –

1. t.plan() should be used before any assertions.
2. t.plan() must be given an argument with the plan count.
3. t.plan() should be used only once inside a test.

Fail

import tap from 'tap';

// Invalid because `t.plan()` is used after an assertion.
tap.test('test name', t => {
	t.ok(true);
    t.plan(1)
	t.end();
});

// Invalid because `t.plan()` was not given the plan count as an argument.
tap.test('test name', t => {
    t.plan()
	t.ok(true);
	t.end();
});

// Invalid because `t.plan()` was used more than once.
tap.test('test name', t => {
    t.plan(1)
	t.ok(true);
    t.notOk(false);
    t.plan(2);
	t.end();
});

Pass

import tap from 'tap';

tap.test('test name', t => {
    t.plan(2);
	t.ok(true);
	t.notOk(false);
	t.end();
});

tap.test('test name', t => {
	t.ok(true);
	t.end();
});