Add test that README contains example from tests/

README.md

@@ -5,11 +5,12 @@ Supports both synchronous and asynchronous assertions.
 
 ## Example
 
+<!-- EXAMPLE -->
 ```rust
 use expecters::prelude::*;
 
 #[tokio::test]
-async fn test() {    
+async fn test() {
     expect!(1, as_display, to_equal("1"));
     expect!(1..=5, count, to_equal(5));
 
@@ -18,13 +19,15 @@ async fn test() {
         all,
         when_ready,
         to_end_with("0.png"),
-    ).await;
+    )
+    .await;
 }
 
 async fn get_cat_url(id: u32) -> String {
     format!("cats/{id}.png")
 }
 ```
+<!-- /EXAMPLE -->
 
 Error message:
 

tests/readme.rs

@@ -0,0 +1,32 @@
+use expecters::prelude::*;
+
+const TEST_CONTENTS: &str = include_str!("./readme_example.rs");
+const README_CONTENTS: &str = include_str!("../README.md");
+
+#[test]
+fn readme_example_is_correct() {
+    let example = get_section("EXAMPLE").expect("example section not found");
+    expect!(example, to_start_with("```rust"));
+    expect!(example, to_end_with("```"));
+
+    // Trim out code block styling and extra attributes and normalize line
+    // endings
+    let example = example["```rust".len()..example.len() - "```".len()]
+        .trim()
+        .replace("\r\n", "\n");
+    let test_contents = TEST_CONTENTS["#![cfg(feature = \"futures\")]".len()..]
+        .split("#[ignore]")
+        .map(|s| s.trim())
+        .collect::<Vec<_>>()
+        .join("\n")
+        .replace("\r\n", "\n");
+    let test_contents = test_contents.trim();
+
+    expect!(example, to_equal(test_contents));
+}
+
+fn get_section(name: &str) -> Option<&'static str> {
+    let (_, rest) = README_CONTENTS.split_once(&format!("<!-- {name} -->"))?;
+    let (contents, _) = rest.split_once(&format!("<!-- /{name} -->"))?;
+    Some(contents.trim())
+}

tests/readme_example.rs

@@ -1,7 +1,9 @@
+#![cfg(feature = "futures")]
+
 use expecters::prelude::*;
 
 #[tokio::test]
-#[ignore = "run this manually to see the output from the README"]
+#[ignore]
 async fn test() {
     expect!(1, as_display, to_equal("1"));
     expect!(1..=5, count, to_equal(5));