TestComponent: Add syntax highlighting behind RUST_LOG

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

Cargo.toml

@@ -16,3 +16,6 @@ log = "^0.4"
 tokio = "^1.20"
 tokio-xmpp = { version = "^3.2", default-features = false, features = ["tls-rust"] }
 xmpp-parsers = { version = "^0.19", features = ["component"] }
+
+[dev-dependencies]
+syntect = "5.0"

src/component/test.rs

@@ -26,6 +26,13 @@ use std::thread;
 
 use async_trait::async_trait;
 use futures::{task::Poll, Stream};
+use log::debug;
+use syntect::{
+	easy::HighlightLines,
+	highlighting::{Style, ThemeSet},
+	parsing::SyntaxSet,
+	util::{as_24_bit_terminal_escaped, LinesWithEndings},
+};
 use xmpp_parsers::{iq::Iq, message::Message, presence::Presence, Element, Jid};
 
 enum Expect {
@@ -118,6 +125,8 @@ pub struct Component {
 
 impl Component {
 	pub fn new(in_buffer: Vec<Element>) -> Self {
+		env_logger::builder().is_test(true).init();
+
 		Component {
 			in_buffer: VecDeque::from(
 				in_buffer
@@ -178,6 +187,22 @@ impl Component {
 		self.add_expect(stream, Expect::Presence(Box::new(callback), desc.into()))
 	}
 
+	fn hl<S: Into<String>>(element: S) -> String {
+		let ps = SyntaxSet::load_defaults_newlines();
+		let syntax = ps.find_syntax_by_extension("xml").unwrap();
+		let ts = ThemeSet::load_defaults();
+
+		let mut buf = String::new();
+		let mut h = HighlightLines::new(syntax, &ts.themes["Solarized (dark)"]);
+		for line in LinesWithEndings::from(&element.into()) {
+			let ranges: Vec<(Style, &str)> = h.highlight_line(line, &ps).unwrap();
+			let escaped = as_24_bit_terminal_escaped(&ranges[..], false);
+			buf.push_str(escaped.as_str());
+		}
+		buf.push_str("\x1b[0m");
+		buf
+	}
+
 	fn send_stanza_inner<E: Into<TestElement> + Send>(&mut self, el: E) -> Result<(), Error> {
 		let out: TestElement = el.into();
 		let dest: Jid = match out.attr("to") {
@@ -193,43 +218,55 @@ impl Component {
 					Some(expected) => match expected {
 						Expect::Element(el) => {
 							let (expected, actual) = (String::from(&el), String::from(&out));
+							let hl_expected = Component::hl(expected.clone());
+							let hl_actual = Component::hl(actual.clone());
 							if expected != actual {
-								panic!(
-									r#"assertion failed: `(actual == expected)`
-  actual: `{}`,
-expected: `{}`"#,
-									actual, expected
-								)
+								debug!(
+									"\nexpected: `{}`\n  \x1b[31mactual\x1b[0m: `{}`\n",
+									hl_expected, hl_actual
+								);
+								panic!("assertion failed: `(actual == expected)`")
+							} else {
+								debug!(
+									"\nexpected: `{}`\n  \x1b[32mactual\x1b[0m: `{}`\n",
+									hl_expected, hl_actual
+								);
 							}
 						}
 						Expect::Iq(cb, _) => match Iq::try_from(out.0.clone()) {
 							Ok(iq) => cb(iq),
 							_ => panic!(
 								"Mismatch stanza type. Expected iq, got: {}",
-								String::from(&out)
+								Component::hl(String::from(&out))
 							),
 						},
 						Expect::Message(cb, _) => match Message::try_from(out.0.clone()) {
 							Ok(message) => cb(message),
 							_ => panic!(
 								"Mismatch stanza type. Expected message, got: {}",
-								String::from(&out)
+								Component::hl(String::from(&out))
 							),
 						},
 						Expect::Presence(cb, _) => match Presence::try_from(out.0.clone()) {
 							Ok(presence) => cb(presence),
 							_ => panic!(
 								"Mismatch stanza type. Expected presence, got: {}",
-								String::from(&out)
+								Component::hl(String::from(&out))
 							),
 						},
 					},
-					None => panic!("Missing matching expected element: {:?}", out),
+					None => panic!(
+						"Missing matching expected element: {:?}",
+						Component::hl(&out)
+					),
 				};
 				// Do we need to remove the empty VecDeque from the HashMap?
 				buf.is_empty()
 			}
-			None => panic!("Missing matching expected element: {:?}", out),
+			None => panic!(
+				"Missing matching expected element: {:?}",
+				Component::hl(&out)
+			),
 		};
 
 		if empty_buf {