Add console_test example to stress-test Tock's console driver.

examples/console_test.rs

@@ -0,0 +1,33 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![no_std]
+
+extern crate lang_items;
+
+use libtock_drivers::console::{Console, BUFFER_SIZE};
+
+fn main() {
+    // Write messages of length up to the console driver's buffer size.
+    let mut buf = [0; BUFFER_SIZE];
+    loop {
+        for i in 1..buf.len() {
+            for j in 0..i {
+                buf[j] = b'0' + ((i % 10) as u8);
+            }
+            buf[i] = b'\n';
+            Console::write_unbuffered(&mut buf[..(i + 1)]);
+        }
+    }
+}