niri-config: add test to see if all snippets inside of the wiki compile

Signed-off-by: Suyashtnt <suyashtnt@gmail.com>

niri-config/Cargo.toml

@@ -20,3 +20,4 @@ tracy-client.workspace = true
 
 [dev-dependencies]
 pretty_assertions = "1.4.0"
+miette = { version = "5.10.0", features = ["fancy"] }

niri-config/tests/wiki-parses.rs

@@ -0,0 +1,108 @@
+use std::fs;
+use std::path::PathBuf;
+
+const NO_TEST_COMMENT: &str = "<!-- no-test -->";
+
+struct KdlCodeBlock {
+    filename: String,
+    code: String,
+    line_number: usize,
+}
+
+fn extract_kdl_from_file(file_contents: &str, filename: &str) -> Vec<KdlCodeBlock> {
+    // Removes the > from callouts that might contain ```kdl```
+    let lines: Vec<_> = file_contents
+        .lines()
+        .map(|line| {
+            let line = line.trim();
+            if line.starts_with(">") {
+                if line.len() == 1 {
+                    ""
+                } else {
+                    &line[2..]
+                }
+            } else {
+                line
+            }
+        })
+        .enumerate()
+        .collect();
+
+    let mut lines_iter = lines.iter();
+    let mut kdl_code_blocks = vec![];
+
+    while let Some((line_number, line)) = lines_iter.next() {
+        let start_snippet =
+            line.starts_with("```kdl") && lines[line_number - 1].1 != NO_TEST_COMMENT;
+
+        if !start_snippet {
+            continue;
+        }
+
+        let mut snippet = String::new();
+        for (_, line) in lines_iter
+            .by_ref()
+            .take_while(|(_, line)| !line.starts_with("```"))
+        {
+            snippet.push_str(line);
+            snippet.push('\n');
+        }
+
+        kdl_code_blocks.push(KdlCodeBlock {
+            code: snippet,
+            line_number: *line_number,
+            filename: filename.to_string(),
+        });
+    }
+
+    kdl_code_blocks
+}
+
+#[test]
+fn wiki_docs_parses() {
+    let wiki_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../wiki");
+
+    let code_blocks = fs::read_dir(&wiki_dir)
+        .unwrap()
+        .filter_map(|entry| entry.ok())
+        .filter(|entry| entry.file_type().is_ok_and(|ft| ft.is_file()))
+        .filter(|file| {
+            file.path()
+                .extension()
+                .map(|ext| ext == "md")
+                .unwrap_or(false)
+        })
+        .map(|file| {
+            let file_contents = fs::read_to_string(file.path()).unwrap();
+            let file_path = file.path();
+            let filename = file_path.to_str().unwrap();
+            extract_kdl_from_file(&file_contents, filename)
+        })
+        .flatten();
+
+    let mut errors = vec![];
+
+    for KdlCodeBlock {
+        code,
+        line_number,
+        filename,
+    } in code_blocks
+    {
+        if let Err(error) = niri_config::Config::parse(&filename, &code) {
+            errors.push(format!(
+                "Error parsing wiki KDL code block at {}:{}: {:?}",
+                filename,
+                line_number,
+                miette::Report::new(error)
+            ))
+        }
+    }
+
+    if !errors.is_empty() {
+        panic!(
+            "Errors parsing {} wiki KDL code blocks:\n{}",
+            errors.len(),
+            errors.join("\n")
+        );
+    }
+}