Allow mixed usage of strings and slices in get_collection

src/client.rs

@@ -204,7 +204,7 @@ pub struct Client<'a> {
 }
 
 impl<'a> Client<'a> {
-    pub fn get_collection<S: Into<Vec<u8>>>(&'a self, db: S, collection: S) -> Collection<'a> {
+    pub fn get_collection<DBT: Into<Vec<u8>>, CT: Into<Vec<u8>>>(&'a self, db: DBT, collection: CT) -> Collection<'a> {
         assert!(!self.inner.is_null());
         let coll = unsafe {
             let db_cstring         = CString::new(db).unwrap();

tests/collection.rs

@@ -23,6 +23,7 @@ fn test_mutation_and_finding() {
     let uri        = Uri::new("mongodb://localhost:27017/").unwrap();
     let pool       = ClientPool::new(uri, None);
     let client     = pool.pop();
+    let _ =  client.get_collection("rust_driver_test".to_string(), "items");
     let mut collection = client.get_collection("rust_driver_test", "items");
     collection.drop().unwrap_or(());