diff --git a/go/packages/packagestest/modules.go b/go/packages/packagestest/modules.go
index 42b62067a8d..2c435674747 100644
--- a/go/packages/packagestest/modules.go
+++ b/go/packages/packagestest/modules.go
@@ -174,7 +174,7 @@ func (modules) Finalize(exported *Exported) error {
 	// stuff in cache. All the files created by Export should be recreated.
 	inv := gocommand.Invocation{
 		Verb:       "mod",
-		Args:       []string{"download"},
+		Args:       []string{"download", "all"},
 		Env:        exported.Config.Env,
 		BuildFlags: exported.Config.BuildFlags,
 		WorkingDir: exported.Config.Dir,
diff --git a/internal/imports/mod_test.go b/internal/imports/mod_test.go
index 91863efacab..51bc9679184 100644
--- a/internal/imports/mod_test.go
+++ b/internal/imports/mod_test.go
@@ -709,7 +709,7 @@ func setup(t *testing.T, main, wd string) *modTest {
 		t.Fatalf("checking if go.mod exists: %v", err)
 	}
 	if err == nil {
-		if _, err := env.invokeGo(context.Background(), "mod", "download"); err != nil {
+		if _, err := env.invokeGo(context.Background(), "mod", "download", "all"); err != nil {
 			t.Fatal(err)
 		}
 	}