fix: don't panic when coverage.reporter is a string

packages/vitest/src/node/config/resolveConfig.ts

@@ -229,6 +229,8 @@ export function resolveConfig(
     )
   }
 
+  resolved.coverage.reporter = toArray(resolved.coverage.reporter)
+
   if (resolved.coverage.enabled && resolved.coverage.reportsDirectory) {
     const reportsDirectory = resolve(
       resolved.root,

test/coverage-test/test/reporters.test.ts

@@ -1,4 +1,5 @@
-import { readdirSync } from 'node:fs'
+import { existsSync, readdirSync } from 'node:fs'
+import { rm } from 'node:fs/promises'
 import { expect } from 'vitest'
 import { runVitest, test } from '../utils'
 
@@ -17,6 +18,23 @@ test('reporter as string', async () => {
   expect(files).toContain('coverage-final.json')
 })
 
+test('reporter as string when coverage is disabled', async () => {
+  if (existsSync('./coverage')) {
+    await rm('./coverage', { recursive: true, force: true })
+  }
+
+  await runVitest({
+    include,
+    coverage: {
+      enabled: false,
+      reporter: 'json',
+      all: false,
+    },
+  })
+
+  expect(existsSync('./coverage')).toBe(false)
+})
+
 test('reporter as list of strings', async () => {
   await runVitest({
     include,