docs: add spans example

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/misc.rs b/tests/misc.rs
index 416e506..0db0606 100644
--- a/tests/misc.rs
+++ b/tests/misc.rs
@@ -1,3 +1,9 @@
+use std::{
+    fs::File,
+    io::{BufRead, BufReader},
+    process::Command,
+};
+
 use similar_asserts::assert_eq;
 use walkdir::{DirEntry, WalkDir};
 
@@ -45,3 +51,31 @@ fn is_source_file(entry: &DirEntry) -> bool {
 
     !filename.starts_with('.') // .git, etc.
 }
+
+#[test]
+fn example_output_in_readme() {
+    let output = Command::new("cargo")
+        .args(["run", "--example", "spans"])
+        .output()
+        .unwrap()
+        .stdout;
+
+    let expected = std::str::from_utf8(&output)
+        .unwrap()
+        .trim_end()
+        .lines()
+        .map(|s| s.trim_end().to_string())
+        .collect::<Vec<_>>()
+        .join("\n");
+
+    let actual = BufReader::new(File::open("README.md").unwrap())
+        .lines()
+        .flatten()
+        .skip_while(|l| l != "```output id=spans")
+        .skip(1)
+        .take_while(|l| l != "```")
+        .collect::<Vec<_>>()
+        .join("\n");
+
+    assert_eq!(actual, expected);
+}