[dschmidt]

Description

Stacked on #3798.

Web always has <base href="/">, and since #3798 the web unit tests add it in vitest.init.ts. Extensions run their unit tests with the test config from defineConfig of the extension SDK, which had no setup file. So an extension test that reaches buildUrl had to add the element itself.

The SDK now ships dist/vitest.setup.js, which adds the element, and sets it as setupFiles in the test config. A setupFiles of the extension is merged in, not replaced (mergeConfig concatenates arrays).

The path is built from dirname(import.meta.url), because Vite turns new URL('./vitest.setup.js', import.meta.url) into an inlined asset at build time.

Related Issue

• fix(pastebin): copy the pastebin view link after creating a pastebin web-extensions#629 has to add the element in its spec for now; this makes that unnecessary.

How Has This Been Tested?

• built the SDK and ran the pastebin unit tests from fix(pastebin): copy the pastebin view link after creating a pastebin web-extensions#629 with it, with the <base> block removed from the spec: they pass, and fail with the released SDK
• an extra setupFiles entry in the extension config runs as well
• type check, eslint, prettier

Types of changes

• Bugfix
• Enhancement (a change that doesn't break existing code or deployments)
• Breaking change (a modification that affects current functionality)
• Technical debt (addressing code that needs refactoring or improvements)
• Tests (adding or improving tests)
• Documentation (updates or additions to documentation)
• Maintenance (like dependency updates or tooling adjustments)