diff --git a/complete.go b/complete.go
index 0641c39..87f376c 100644
--- a/complete.go
+++ b/complete.go
@@ -53,6 +53,14 @@ var (
 	exit   = os.Exit
 )
 
+// SetExitFunc sets the function used to exit the program (by default os.Exit)
+// and returns the previous value.
+func SetExitFunc(fn func(code int)) (previous func(int)) {
+	previous = exit
+	exit = fn
+	return previous
+}
+
 // Complete the command line arguments for the given command in the case that the program
 // was invoked with COMP_LINE and COMP_POINT environment variables. In that case it will also
 // `os.Exit()`. The program name should be provided for installation purposes.
diff --git a/go.mod b/go.mod
index f510a56..3cdbf29 100644
--- a/go.mod
+++ b/go.mod
@@ -3,14 +3,16 @@ module github.com/posener/complete/v2
 go 1.20
 
 require (
-	bou.ke/monkey v1.0.2
 	github.com/posener/autogen v0.0.3
 	github.com/posener/script v1.2.0
 	github.com/stretchr/testify v1.8.4
+	golang.org/x/tools v0.35.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	golang.org/x/mod v0.26.0 // indirect
+	golang.org/x/sync v0.16.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
diff --git a/go.sum b/go.sum
index ee4b3b5..3e2bb06 100644
--- a/go.sum
+++ b/go.sum
@@ -1,7 +1,7 @@
-bou.ke/monkey v1.0.2 h1:kWcnsrCNUatbxncxR/ThdYqbytgOIArtYWqcQLQzKLI=
-bou.ke/monkey v1.0.2/go.mod h1:OqickVX3tNx6t33n1xvtTtu85YN5s6cKwVug+oHMaIA=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/posener/autogen v0.0.3 h1:V3e1E2GiNhK3yzd26NA7TiYCgeFuNkv1CkHlXJ7sqzA=
@@ -10,6 +10,12 @@ github.com/posener/script v1.2.0 h1:DrZz0qFT8lCLkYNi1PleLDANFnKxJ2VmlNPJbAkVLsE=
 github.com/posener/script v1.2.0/go.mod h1:s4sVvRXtdc/1aK6otTSeW2BVXndO8MsoOVUwK74zcg4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+golang.org/x/mod v0.26.0 h1:EGMPT//Ezu+ylkCijjPc+f4Aih7sZvaAr+O3EHBxvZg=
+golang.org/x/mod v0.26.0/go.mod h1:/j6NAhSk8iQ723BGAUyoAcn7SlD7s15Dp9Nd/SfeaFQ=
+golang.org/x/sync v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
+golang.org/x/sync v0.16.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
+golang.org/x/tools v0.35.0 h1:mBffYraMEf7aa0sB+NuKnuCy8qI/9Bughn8dC2Gu5r0=
+golang.org/x/tools v0.35.0/go.mod h1:NKdj5HkL/73byiZSJjqJgKn3ep7KjFkBOkR/Hps3VPw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
diff --git a/gocomplete/tests_test.go b/gocomplete/tests_test.go
index dbe72cf..8696878 100644
--- a/gocomplete/tests_test.go
+++ b/gocomplete/tests_test.go
@@ -11,7 +11,6 @@ import (
 	"strings"
 	"testing"
 
-	"bou.ke/monkey"
 	"github.com/posener/complete/v2"
 )
 
@@ -53,8 +52,8 @@ func TestPredictions(t *testing.T) {
 func BenchmarkFake(b *testing.B) {}
 
 func Example() {
-	p := monkey.Patch(os.Exit, func(int) {})
-	defer p.Unpatch()
+	p := complete.SetExitFunc(func(int) {})
+	defer complete.SetExitFunc(p)
 	os.Setenv("COMP_LINE", "go ru")
 	os.Setenv("COMP_POINT", "5")
 	main()
@@ -76,7 +75,8 @@ func equal(s1, s2 []string) bool {
 }
 
 func TestErrorSupression(t *testing.T) {
-	defer monkey.Patch(os.Exit, func(int) {}).Unpatch()
+	p := complete.SetExitFunc(func(int) {})
+	defer complete.SetExitFunc(p)
 
 	// Completion API environment variable names.
 	const envLine, envPoint = "COMP_LINE", "COMP_POINT"