channeldb: move makeTestDB out of test to make it available for other tests

This commit moves makeTestDB to db.go and exports it so that we'll be
able to use this function in other unit tests to make them testable with
etcd if needed.

channeldb/forwarding_log_test.go

@@ -19,7 +19,7 @@ func TestForwardingLogBasicStorageAndQuery(t *testing.T) {
 	// First, we'll set up a test database, and use that to instantiate the
 	// forwarding event log that we'll be using for the duration of the
 	// test.
-	db, cleanUp, err := makeTestDB()
+	db, cleanUp, err := MakeTestDB()
 	defer cleanUp()
 	if err != nil {
 		t.Fatalf("unable to make test db: %v", err)
@@ -91,7 +91,7 @@ func TestForwardingLogQueryOptions(t *testing.T) {
 	// First, we'll set up a test database, and use that to instantiate the
 	// forwarding event log that we'll be using for the duration of the
 	// test.
-	db, cleanUp, err := makeTestDB()
+	db, cleanUp, err := MakeTestDB()
 	defer cleanUp()
 	if err != nil {
 		t.Fatalf("unable to make test db: %v", err)
@@ -196,7 +196,7 @@ func TestForwardingLogQueryLimit(t *testing.T) {
 	// First, we'll set up a test database, and use that to instantiate the
 	// forwarding event log that we'll be using for the duration of the
 	// test.
-	db, cleanUp, err := makeTestDB()
+	db, cleanUp, err := MakeTestDB()
 	defer cleanUp()
 	if err != nil {
 		t.Fatalf("unable to make test db: %v", err)