cmd/go: fuzzing doesn't work with environment startup

[Ferrany1]

What version of Go are you using (go version)?

go version go1.18 darwin/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

GOHOSTARCH="amd64"
GOHOSTOS="darwin"

What did you do?

Running fuzz test with environment (containers with https://github.com/testcontainers/testcontainers-go and services in runtime) to test api routes

//go:build fuzzing

package main

import (
	"bytes"
	"context"
	"net/http"
	"testing"

	"github.com/stretchr/testify/require"
	"github.com/testcontainers/testcontainers-go"
	"github.com/testcontainers/testcontainers-go/wait"
)

func FuzzFoo(f *testing.F) {
	initEnvironment(f)
	f.Add("first")
	f.Fuzz(
		func(t *testing.T, tenant string) {
			t.Run("testFoo", func(t *testing.T) { testFoo(t, tenant) })
		},
	)
}

func initEnvironment(tb testing.TB) {
	ctx := context.Background()
	_, err := testcontainers.GenericNetwork(
		ctx,
		testcontainers.GenericNetworkRequest{
			NetworkRequest: testcontainers.NetworkRequest{
				Name:        "test_fuzz",
				ReaperImage: testcontainers.ReaperDefaultImage,
			},
		},
	)
	require.NoError(tb, err)

	containerRequest := testcontainers.ContainerRequest{
		Name:  "cocroach-fuzz",
		Image: "cockroachdb/cockroach:v21.1.11",
		Cmd:   []string{"start-single-node", "--insecure"},
		ExposedPorts: []string{
			"127.0.0.1:26257:26257/tcp",
			"127.0.0.1:8080:8080/tcp",
		},
		WaitingFor:  wait.ForListeningPort("26257/tcp"),
		ReaperImage: testcontainers.ReaperDefaultImage,
		Networks:    []string{"test_fuzz"},
	}
	require.NoError(tb, err)

	container, err := testcontainers.GenericContainer(
		ctx,
		testcontainers.GenericContainerRequest{
			ContainerRequest: containerRequest,
			Started:          false,
		},
	)
	require.NoError(tb, err)
	err = container.Start(ctx)
	require.NoError(tb, err)

	err = container.StartLogProducer(ctx)
	require.NoError(tb, err)

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
	})
	s := http.Server{Addr: "0.0.0.0:8090"}
	go s.ListenAndServe()
}

func testFoo(tb testing.TB, tenant string) {
	request, err := http.NewRequest(http.MethodPut, "http://127.0.0.1:8090/", bytes.NewBuffer([]byte(tenant)))
	require.NoError(tb, err)

	response, err := http.DefaultClient.Do(request)
	require.NoError(tb, err)
	defer func() {
		require.NoError(tb, response.Body.Close())
	}()
	require.Equal(tb, http.StatusOK, response.StatusCode)
}

Command: go test -fuzz=FuzzFoo -tags fuzzing -test.fuzztime 3m ./fuzz_test.go

Starting without initializing environment produces correct output

What did you expect to see?

fuzz: elapsed: 0s, gathering baseline coverage: 1/1 completed, now fuzzing with 4 workers

What did you see instead?

fuzz: elapsed: 0s, gathering baseline coverage: 0/1 completed
fuzz: elapsed: 0s, gathering baseline coverage: 0/1 completed
--- FAIL: FuzzFoo (15.07s)
    fuzzing process terminated without fuzzing: EOF
FAIL
exit status 1

[Ferrany1]

Seems like problem occurs because of testcontainers lib

[seankhliao]

please fill out the issue template properly and include a self contained, reproducible example

[Ferrany1]

please fill out the issue template properly and include a self contained, reproducible example

Added example with command, as I mentioned above it seems like testcontainers lib somehow affects fuzzing, because without it everything is fine

[Ferrany1]

please fill out the issue template properly and include a self contained, reproducible example

Anything else needed?

[seankhliao]

Fuzzing runs multiple subprocesses so it can catch crashes. Your use of testcontainers isn't compatible with that, the processes compete for shared global (OS) resources.
The bad error message is from testcontainers not reporting a proper error.

[Ferrany1]

Fuzzing runs multiple subprocesses so it can catch crashes. Your use of testcontainers isn't compatible with that, the processes compete for shared global (OS) resources. The bad error message is from testcontainers not reporting a proper error.

But it seems okay if i start containers manually in docker, so it occurs because of some inner testcontainer work?
However it work okay in unit tests without any errors produced on side of testcontainers

[mdonkers]

In case others come across this, the solution is adding -parallel 1 as parameter to the fuzzing test.
At least in my scenario running fuzzing against a testcontainer (DB to verify string formatting) worked fine.