CoapClient

- Added `setExchangeLifetime(Duration)`

CoapClient (unittests)

- Manually set the exchange lifetime

source/doap/client/client.d

@@ -104,6 +104,19 @@ public class CoapClient
      */
     private Duration EXCHANGE_LIFETIME = dur!("msecs")(180);
 
+    /** 
+     * Sets the exchange lifetime. In other words
+     * the duration of time that must pass before
+     * a message ID is considered free-for-use again
+     *
+     * Params:
+     *   lifetime = the lifetime duration
+     */
+    public void setExchangeLifetime(Duration lifetime)
+    {
+        this.EXCHANGE_LIFETIME = lifetime;
+    }
+
     /** 
      * Generates a new message ID
      *
@@ -381,7 +394,15 @@ version(unittest)
 /**
  * Client testing
  *
- * Tests the rolling of the message id
+ * Tests the rolling of the message id,
+ * here I configure the `EXCHANGE_LIFETIME`
+ * to be a value high enough to not have
+ * them quickly expire.
+ *
+ * NOTE: In the future it may be calculated
+ * in relation to other variables and we may
+ * need a private method accessible here that
+ * can override it
  */
 unittest
 {
@@ -394,6 +415,8 @@ unittest
                               .post();
 
 
+    client.setExchangeLifetime(dur!("msecs")(180));
+
     writeln("Future start (first)");
     CoapPacket response = future.get();
     writeln("Future done (first)");