RUST-589 Implement FromStr for ObjectId (#215)

Author: forgerpl

src/oid.rs

@@ -5,6 +5,7 @@ use std::{
     error,
     fmt,
     result,
+    str::FromStr,
     sync::atomic::{AtomicUsize, Ordering},
     time::SystemTime,
 };
@@ -79,6 +80,14 @@ impl Default for ObjectId {
     }
 }
 
+impl FromStr for ObjectId {
+    type Err = Error;
+
+    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
+        Self::with_string(s)
+    }
+}
+
 impl ObjectId {
     /// Generates a new ObjectID, represented in bytes.
     /// See the [docs](http://docs.mongodb.org/manual/reference/object-id/)

src/tests/modules/oid.rs

@@ -47,3 +47,13 @@ fn counter_increasing() {
     let oid2_bytes = ObjectId::new().bytes();
     assert!(oid1_bytes[11] < oid2_bytes[11]);
 }
+
+#[test]
+fn fromstr_oid() {
+    let _guard = LOCK.run_concurrently();
+    let s = "123456789012123456789012";
+    let oid_res = s.parse::<ObjectId>();
+    assert!(oid_res.is_ok(), "oid parse failed");
+    let actual_s = hex::encode(oid_res.unwrap().bytes());
+    assert_eq!(s, &actual_s, "parsed and expected oids differ");
+}