component: impl Debug for Expect

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>

src/component.rs

@@ -6,6 +6,7 @@
 
 use crate::error::Error;
 
+use std::fmt;
 use std::marker::Send;
 use std::ops::{Deref, DerefMut};
 use std::pin::Pin;
@@ -80,6 +81,17 @@ enum Expect {
     Callback(Box<dyn FnOnce(Element) + Send + 'static>),
 }
 
+impl fmt::Debug for Expect {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Expect::")?;
+        match self {
+            Expect::Element(el) => write!(f, "Element({:?})", String::from(el)),
+            Expect::Callback(_) => write!(f, "Callback(<cb>)"),
+        }
+    }
+}
+
+#[derive(Debug)]
 pub struct TestComponent {
     in_buffer: Vec<Element>,
     out_buffer: Vec<Element>,