diff --git a/cmd/cue/cmd/script_test.go b/cmd/cue/cmd/script_test.go
index 004b5e4..43012c9 100644
--- a/cmd/cue/cmd/script_test.go
+++ b/cmd/cue/cmd/script_test.go
@@ -26,6 +26,7 @@
 	"strings"
 	"testing"
 
+	"github.com/rogpeppe/go-internal/goproxytest"
 	"github.com/rogpeppe/go-internal/gotooltest"
 	"github.com/rogpeppe/go-internal/testscript"
 	"github.com/rogpeppe/go-internal/txtar"
@@ -37,7 +38,8 @@
 // TestLatest checks that the examples match the latest language standard,
 // even if still valid in backwards compatibility mode.
 func TestLatest(t *testing.T) {
-	filepath.Walk("testdata/script", func(fullpath string, info os.FileInfo, err error) error {
+	root := filepath.Join("testdata", "script")
+	filepath.Walk(root, func(fullpath string, info os.FileInfo, err error) error {
 		if !strings.HasSuffix(fullpath, ".txt") ||
 			strings.HasPrefix(filepath.Base(fullpath), "fix") {
 			return nil
@@ -72,9 +74,20 @@
 }
 
 func TestScript(t *testing.T) {
+	srv, err := goproxytest.NewServer(filepath.Join("testdata", "mod"), "")
+	if err != nil {
+		t.Fatalf("cannot start proxy: %v", err)
+	}
 	p := testscript.Params{
-		Dir:           "testdata/script",
+		Dir:           filepath.Join("testdata", "script"),
 		UpdateScripts: *update,
+		Setup: func(e *testscript.Env) error {
+			e.Vars = append(e.Vars,
+				"GOPROXY="+srv.URL,
+				"GONOSUMDB=*", // GOPROXY is a private proxy
+			)
+			return nil
+		},
 	}
 	if err := gotooltest.Setup(&p); err != nil {
 		t.Fatal(err)
diff --git a/cmd/cue/cmd/testdata/mod/example.com_blah_v1.0.0.txt b/cmd/cue/cmd/testdata/mod/example.com_blah_v1.0.0.txt
new file mode 100644
index 0000000..0fc3b23
--- /dev/null
+++ b/cmd/cue/cmd/testdata/mod/example.com_blah_v1.0.0.txt
@@ -0,0 +1,18 @@
+-- .mod --
+module example.com/blah
+
+-- .info --
+{"Version":"v1.0.0","Time":"2018-10-22T18:45:39Z"}
+
+-- go.mod --
+module example.com/blah
+
+-- blah.go --
+package blah
+
+// Some fruit
+const Name = "Orange"
+-- blah.cue --
+package blah
+
+Type: "Fruit"
diff --git a/cmd/cue/cmd/testdata/script/goproxytest.txt b/cmd/cue/cmd/testdata/script/goproxytest.txt
new file mode 100644
index 0000000..549e027
--- /dev/null
+++ b/cmd/cue/cmd/testdata/script/goproxytest.txt
@@ -0,0 +1,29 @@
+# Basic test to ensure that the goproxytest instance used by various testscript
+# tests works as expected.
+
+go get example.com/blah
+go mod tidy
+cmp go.mod go.mod.golden
+
+-- go.mod --
+module rubbish
+
+go 1.14
+-- main.go --
+package main
+
+import (
+	"fmt"
+
+	"example.com/blah"
+)
+
+func main() {
+	fmt.Println(blah.Orange)
+}
+-- go.mod.golden --
+module rubbish
+
+go 1.14
+
+require example.com/blah v1.0.0