src/cmd/go/testdata/script/test_fuzz_mutate_crash.txt

# Tests that a crash caused by a mutator-discovered input writes the bad input
# to testdata, and fails+reports correctly. This tests the end-to-end behavior
# of the mutator finding a crash while fuzzing, adding it as a regression test
# to the seed corpus in testdata, and failing the next time the test is run.

[short] skip

# TODO: remove -parallel=1 once the races are fixed.

# Running the seed corpus for all of the targets should pass the first
# time, since nothing in the seed corpus will cause a crash.
go test -parallel=1

# Running the fuzzer should find a crashing input quickly.
! go test -fuzz=FuzzWithBug -parallel=1
stdout 'testdata/corpus/FuzzWithBug/fb8e20fc2e4c3f248c60c39bd652f3c1347298bb977b8b4d5903b85055620603'
stdout 'this input caused a crash!'
grep '\Aab\z' testdata/corpus/FuzzWithBug/fb8e20fc2e4c3f248c60c39bd652f3c1347298bb977b8b4d5903b85055620603

# Now, the failing bytes should have been added to the seed corpus for
# the target, and should fail when run without fuzzing.
! go test -parallel=1

! go test -run=FuzzWithNilPanic -fuzz=FuzzWithNilPanic -parallel=1
stdout 'testdata/corpus/FuzzWithNilPanic/f45de51cdef30991551e41e882dd7b5404799648a0a00753f44fc966e6153fc1'
stdout 'runtime.Goexit'
grep '\Aac\z' testdata/corpus/FuzzWithNilPanic/f45de51cdef30991551e41e882dd7b5404799648a0a00753f44fc966e6153fc1

! go test -run=FuzzWithBadExit -fuzz=FuzzWithBadExit -parallel=1
stdout 'testdata/corpus/FuzzWithBadExit/70ba33708cbfb103f1a8e34afef333ba7dc021022b2d9aaa583aabb8058d8d67'
stdout 'unexpectedly'
grep '\Aad\z' testdata/corpus/FuzzWithBadExit/70ba33708cbfb103f1a8e34afef333ba7dc021022b2d9aaa583aabb8058d8d67

-- fuzz_crash_test.go --
package fuzz_crash

import (
	"bytes"
    "os"
	"testing"
)

func FuzzWithBug(f *testing.F) {
	f.Add([]byte("aa"))
	f.Fuzz(func(t *testing.T, b []byte) {
		if bytes.Equal(b, []byte("ab")) {
			panic("this input caused a crash!")
		}
	})
}

func FuzzWithNilPanic(f *testing.F) {
	f.Add([]byte("aa"))
	f.Fuzz(func(t *testing.T, b []byte) {
		if bytes.Equal(b, []byte("ac")) {
			panic(nil)
		}
	})
}

func FuzzWithBadExit(f *testing.F) {
	f.Add([]byte("aa"))
	f.Fuzz(func(t *testing.T, b []byte) {
		if bytes.Equal(b, []byte("ad")) {
			os.Exit(1)
		}
	})
}