Added a couple of test cases for sending messages. One works as expected, the other succeeds unexpectedly.

src/test/run-fail/trivial-message2.rs

@@ -0,0 +1,14 @@
+/*
+  This program should hang on the r <- po line.
+ */
+
+fn main() {
+    let port[int] po = port();
+    let chan[int] ch = chan(po);
+
+    auto r <- po;
+
+    ch <| 42;
+
+    log_err r;
+}

src/test/run-pass/trivial-message.rs

@@ -0,0 +1,15 @@
+/*
+  This is about the simplest program that can successfully send a
+  message.
+ */
+
+fn main() {
+    let port[int] po = port();
+    let chan[int] ch = chan(po);
+
+    ch <| 42;
+
+    auto r <- po;
+
+    log_err r;
+}