test verifying size of a Trade struct

src/lib.rs

@@ -49,4 +49,22 @@ mod tests {
             Ok(false)
         ));
     }
+
+    #[test]
+    fn memory_size_of_trades_struct() {
+        use markets::crypto::{Exchange, Ticker, Side};
+
+        struct Trade {
+            pub time: u64,
+            pub price: f64,
+            pub amount: f64,
+            pub exch: Exchange,
+            pub ticker: Ticker,
+            pub server_time: Option<u64>,
+            pub side: Option<Side>,
+        }
+
+        assert_eq!(std::mem::size_of::<Trade>(), 48);
+        assert_eq!(std::mem::size_of::<Ticker>(), 2);
+    }
 }