RUST-390 Implement ordering for Timestamp (#182)

Author: isabelatkinson

src/bson.rs

@@ -985,7 +985,7 @@ impl Bson {
 }
 
 /// Represents a BSON timestamp value.
-#[derive(Debug, Eq, PartialEq, Clone, Copy, Hash)]
+#[derive(Debug, Eq, Ord, PartialEq, PartialOrd, Clone, Copy, Hash)]
 pub struct Timestamp {
     /// The number of seconds since the Unix epoch.
     pub time: u32,

tests/modules/bson.rs

@@ -7,6 +7,7 @@ use bson::{
     Document,
     JavaScriptCodeWithScope,
     Regex,
+    Timestamp,
 };
 use serde_json::{json, Value};
 
@@ -140,3 +141,22 @@ fn from_impls() {
     let db_pointer = db_pointer.as_db_pointer().unwrap();
     assert_eq!(Bson::from(db_pointer), Bson::DbPointer(db_pointer.clone()));
 }
+
+#[test]
+fn timestamp_ordering() {
+    let ts1 = Timestamp {
+        time: 0,
+        increment: 1,
+    };
+    let ts2 = Timestamp {
+        time: 0,
+        increment: 2,
+    };
+    let ts3 = Timestamp {
+        time: 1,
+        increment: 0,
+    };
+    assert!(ts1 < ts2);
+    assert!(ts1 < ts3);
+    assert!(ts2 < ts3);
+}