feat: allow augmenting config.test.env (#5784)

Author: sheremet-va

docs/config/index.md

@@ -2292,3 +2292,9 @@ This is a low-level option and should be used only for advanced cases where you
 
 If you just need to configure snapshots feature, use [`snapshotFormat`](#snapshotformat) or [`resolveSnapshotPath`](#resolvesnapshotpath) options.
 :::
+
+### env {#env}
+
+- **Type:** `Partial<NodeJS.ProcessEnv>`
+
+Environment variables available on `process.env` and `import.meta.env` during tests. These variables will not be available in the main process (in `globalSetup`, for example).

packages/vitest/src/types/config.ts

@@ -579,7 +579,7 @@ export interface InlineConfig {
   /**
    * Custom environment variables assigned to `process.env` before running tests.
    */
-  env?: Record<string, string>
+  env?: Partial<NodeJS.ProcessEnv>
 
   /**
    * Options for @sinon/fake-timers