Enable clear/purge for failed digests

go/util/caching_test.go

Index: go/util/caching_test.go
diff --git a/go/util/caching_test.go b/go/util/caching_test.go
index f5cdb7b46b4f385ace1ee8864cb197a67b4f019a..456ab08ce72d82f936492a1c8dc9e2429a9cfced 100644
--- a/go/util/caching_test.go
+++ b/go/util/caching_test.go
@@ -7,11 +7,6 @@ import (
 )
 
 func TestJSONCodec(t *testing.T) {
-	type myTestType struct {
-		A int
-		B string
-	}
-
 	itemCodec := JSONCodec(&myTestType{})
 	testInstance := &myTestType{5, "hello"}
 	jsonBytes, err := itemCodec.Encode(testInstance)
@@ -32,3 +27,8 @@ func TestJSONCodec(t *testing.T) {
 	assert.IsType(t, []*myTestType{}, decodedArr)
 	assert.Equal(t, testArr, decodedArr)
 }
+
+func TestMemLRUCache(t *testing.T) {
+	cache := NewMemLRUCache(0)
+	UnitTestLRUCache(t, cache)
+}