vitest fails a shard if the shard index is higher than the number of test files.
For example, let's say there is only a single test file but you instruct vitest to split up
the test suite into two shards. While the first shard will pass, the second shard will fail
claiming that there are no test files found.
❯ npm run test:shard-2
> test:shard-2
> vitest run --shard=2/2
RUN v3.2.1 /Users/niklaas/git/red-guava/mre-vitest-shard-missing-files
No test files found, exiting with code 1
include: **/*.{test,spec}.?(c|m)[jt]s?(x)
exclude: **/node_modules/**, **/dist/**, **/cypress/**, **/.{idea,git,cache,output,temp}/**, **/{karma,rollup,webpack,vite,vitest,jest,ava,babel,nyc,cypress,tsup,build,eslint,prettier}.config.*
You can add the --passWithNotTests flag. However, this could cause you to miss out on no tests
being executed for the first shard.