ci: enable clippy lints (#1335)

tokio-test/src/clock.rs

@@ -138,6 +138,12 @@ impl MockClock {
     }
 }
 
+impl Default for MockClock {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Handle {
     pub(self) fn new(timer: Timer<MockPark>, time: MockTime) -> Self {
         Handle { timer, time }

tokio-test/src/io.rs

@@ -187,11 +187,8 @@ impl Inner {
             return Err(io::ErrorKind::BrokenPipe.into());
         }
 
-        match self.action() {
-            Some(&mut Action::Wait(..)) => {
-                return Err(io::ErrorKind::WouldBlock.into());
-            }
-            _ => {}
+        if let Some(&mut Action::Wait(..)) = self.action() {
+            return Err(io::ErrorKind::WouldBlock.into());
         }
 
         for i in 0..self.actions.len() {

tokio-test/src/task.rs

@@ -98,6 +98,12 @@ impl MockTask {
     }
 }
 
+impl Default for MockTask {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl ThreadWaker {
     fn new() -> Self {
         ThreadWaker {