fix(coverage): prevent c8 from crashing on invalid sourcemaps (#2634)

Author: AriPerkkio

packages/coverage-c8/src/provider.ts

@@ -86,6 +86,7 @@ export class C8CoverageProvider implements CoverageProvider {
           entry.map.mappings.length > 0
           && entry.map.sourcesContent
           && entry.map.sourcesContent.length > 0
+          && entry.map.sourcesContent[0]
           && entry.map.sourcesContent[0].length > 0
         )
       }) as SourceMapMeta[]

test/coverage-test/test/no-esbuild-transform.test.js

@@ -0,0 +1,10 @@
+import { expect, test, vi } from 'vitest'
+import { add } from '../src/utils'
+
+vi.mock('../src/utils', async () => ({
+  add: vi.fn().mockReturnValue('mocked'),
+}))
+
+test('mocking in Javascript test should not break sourcemaps', () => {
+  expect(add(1, 2)).toBe('mocked')
+})

test/coverage-test/testing.mjs

@@ -8,7 +8,7 @@ const provider = getArgument('--provider')
 const configs = [
   // Run test cases. Generates coverage report.
   ['test/', {
-    include: ['test/*.test.ts'],
+    include: ['test/*.test.*'],
     exclude: ['coverage-report-tests/**/*'],
   }],