vitest/prefer-lowercase-title

Vitest prints a title after the titles of the blocks around it, as in cart > adds an item. A capital in the middle of that line reads like the start of a new sentence, and a mix of both styles is harder to scan.

bench titles are checked too.

--fix makes the first letter lowercase. Snapshots are stored under their test's title, so update them afterwards.

Configure

Off by default. To turn it on:

[lint.rules]
"vitest/prefer-lowercase-title" = "error" # or "warn"

Every option, set to its default:

[lint.rules]
"vitest/prefer-lowercase-title" = ["error", {
  ignore = [],
  allowedPrefixes = [], # list of strings
  ignoreTopLevelDescribe = false,
  lowercaseFirstCharacterOnly = true,
}]

Examples

Reported:

import { expect, test } from "vitest";

test("Adds an item", () => {
  expect(cart.add(item)).toBe(1);
});

import { bench } from "vitest";

bench("Sorts 1000 items", () => {
  items.toSorted();
});

Not reported:

import { expect, test } from "vitest";

test("adds an item", () => {
  expect(cart.add(item)).toBe(1);
});

Options

Option	Default	What it does
ignore	[]	Functions to skip: "describe", "test", "it", "bench". "test" doesn't cover it.
allowedPrefixes	[]	Allow a title that starts with one of these strings.
ignoreTopLevelDescribe	false	Allow a capital in a describe that isn't inside another block.
lowercaseFirstCharacterOnly	true	Set it to false to report an uppercase letter anywhere in the title. --fix then makes the whole title lowercase.

allowedPrefixes is for titles that start with a name you can't change:

import { test } from "vitest";

test("GET /users returns a list", () => {});

With ignoreTopLevelDescribe, the outer describe can be named after a class or a component. Only "Checkout" is reported here:

import { describe, test } from "vitest";

describe("Cart", () => {
  describe("Checkout", () => {
    test("adds an item", () => {});
  });
});

With { "lowercaseFirstCharacterOnly": false }:

import { test } from "vitest";

test("adds an Item", () => {});