fix bug that multi db use the dafult database, and add related test case

database.go

@@ -66,14 +66,14 @@ func (db *Database) CollectionsDo(f func(c ...*mgo.Collection), names ...string)
 }
 
 func (db *Database) Save(collectionName string, obj Id) (err error) {
-	CollectionDo(collectionName, func(rc *mgo.Collection) {
+	db.CollectionDo(collectionName, func(rc *mgo.Collection) {
 		_, err = rc.Upsert(bson.M{"_id": obj.MakeId()}, obj)
 	})
 	return
 }
 
 func (db *Database) DropCollection(collectionName string) (err error) {
-	CollectionDo(collectionName, func(rc *mgo.Collection) {
+	db.CollectionDo(collectionName, func(rc *mgo.Collection) {
 		err = rc.DropCollection()
 	})
 	return
@@ -92,14 +92,14 @@ func (db *Database) DropCollections(collectionNames ...string) (err error) {
 }
 
 func (db *Database) Delete(collectionName string, id interface{}) (err error) {
-	CollectionDo(collectionName, func(rc *mgo.Collection) {
+	db.CollectionDo(collectionName, func(rc *mgo.Collection) {
 		_, err = rc.RemoveAll(bson.M{"_id": id})
 	})
 	return
 }
 
 func (db *Database) Update(collectionName string, obj Id) (err error) {
-	CollectionDo(collectionName, func(rc *mgo.Collection) {
+	db.CollectionDo(collectionName, func(rc *mgo.Collection) {
 		v := reflect.ValueOf(obj)
 		if v.Kind() == reflect.Ptr {
 			v = v.Elem()
@@ -128,21 +128,21 @@ func (db *Database) Update(collectionName string, obj Id) (err error) {
 }
 
 func (db *Database) FindAll(collectionName string, query interface{}, result interface{}) (err error) {
-	CollectionDo(collectionName, func(c *mgo.Collection) {
+	db.CollectionDo(collectionName, func(c *mgo.Collection) {
 		err = c.Find(query).All(result)
 	})
 	return
 }
 
 func (db *Database) FindOne(collectionName string, query interface{}, result interface{}) (err error) {
-	CollectionDo(collectionName, func(c *mgo.Collection) {
+	db.CollectionDo(collectionName, func(c *mgo.Collection) {
 		err = c.Find(query).One(result)
 	})
 	return
 }
 
 func (db *Database) FindById(collectionName string, id interface{}, result interface{}) (err error) {
-	CollectionDo(collectionName, func(c *mgo.Collection) {
+	db.CollectionDo(collectionName, func(c *mgo.Collection) {
 		err = c.Find(bson.M{"_id": id}).One(result)
 	})
 	return

database_test.go

@@ -0,0 +1,40 @@
+package mgodb
+
+import (
+	"labix.org/v2/mgo"
+	"labix.org/v2/mgo/bson"
+	"testing"
+)
+
+const (
+	ALLUSERS = "allusers"
+	DB1      = "mogdb_test_1"
+	DB2      = "mogdb_test_2"
+)
+
+func TestSave(t *testing.T) {
+	db := NewDatabase("localhost", DB1)
+
+	db.Save(ALLUSERS, &User{Email: "sunfmin@gmail.com", Name: "Felix Sun"})
+
+	var found *User
+	db.CollectionDo(ALLUSERS, func(uc *mgo.Collection) {
+		uc.Find(bson.M{"email": "sunfmin@gmail.com"}).One(&found)
+	})
+	if found == nil {
+		t.Error("Can not find user after saved")
+	}
+
+	db = NewDatabase("localhost", DB2)
+
+	db.Save(ALLUSERS, &User{Email: "sunfmin@gmail.com", Name: "Felix Sun"})
+
+	var u2 *User
+	db.CollectionDo(ALLUSERS, func(uc *mgo.Collection) {
+		uc.Find(bson.M{"email": "sunfmin@gmail.com"}).One(&u2)
+	})
+	if u2 == nil {
+		t.Error("Can not find user after saved")
+	}
+
+}