diff --git a/libgo/go/mime/type_test.go b/libgo/go/mime/type_test.go
index 5e4d25c..5769c6a 100644
--- a/libgo/go/mime/type_test.go
+++ b/libgo/go/mime/type_test.go
@@ -14,7 +14,10 @@
 func setMimeInit(fn func()) (cleanup func()) {
 	once = sync.Once{}
 	testInitMime = fn
-	return func() { testInitMime = nil }
+	return func() {
+		testInitMime = nil
+		once = sync.Once{}
+	}
 }
 
 func clearMimeTypes() {
diff --git a/libgo/go/mime/type_unix_test.go b/libgo/go/mime/type_unix_test.go
index 4d109aa..43db44b 100644
--- a/libgo/go/mime/type_unix_test.go
+++ b/libgo/go/mime/type_unix_test.go
@@ -11,6 +11,7 @@
 )
 
 func initMimeUnixTest(t *testing.T) {
+	once.Do(initMime)
 	err := loadMimeGlobsFile("testdata/test.types.globs2")
 	if err != nil {
 		t.Fatal(err)