use clap for parsing tests. (#876)

Cargo.lock

@@ -2081,6 +2081,7 @@ dependencies = [
 name = "typst-tests"
 version = "0.2.0"
 dependencies = [
+ "clap 4.2.4",
  "comemo",
  "elsa",
  "iai",

tests/Cargo.toml

@@ -17,6 +17,7 @@ tiny-skia = "0.6.2"
 ttf-parser = "0.17"
 unscanny = "0.1"
 walkdir = "2"
+clap = { version = "4.2.1", features = ["derive"] }
 
 [[test]]
 name = "tests"

tests/src/tests.rs

@@ -2,7 +2,6 @@
 
 use std::cell::{RefCell, RefMut};
 use std::collections::HashMap;
-use std::env;
 use std::ffi::OsStr;
 use std::fs;
 use std::ops::Range;
@@ -33,10 +32,53 @@ const PDF_DIR: &str = "pdf";
 const FONT_DIR: &str = "../assets/fonts";
 const FILE_DIR: &str = "../assets/files";
 
-fn main() {
+use clap::Parser;
-    let args = Args::new(env::args().skip(1));
-    let mut filtered = Vec::new();
 
+#[derive(Debug, Clone, Parser)]
+#[clap(name = "typst-test", author)]
+struct Args {
+    filter: Vec<String>,
+    /// runs only the specified subtest
+    #[arg(short, long)]
+    subtest: Option<usize>,
+    #[arg(long)]
+    exact: bool,
+    #[arg(long)]
+    update: bool,
+    #[arg(long)]
+    pdf: bool,
+    #[command(flatten)]
+    print: PrintConfig,
+    #[arg(long)]
+    nocapture: bool, // simply ignores the argument
+}
+
+/// Which things to print out for debugging.
+#[derive(Default, Debug, Copy, Clone, Eq, PartialEq, Parser)]
+struct PrintConfig {
+    #[arg(long)]
+    syntax: bool,
+    #[arg(long)]
+    model: bool,
+    #[arg(long)]
+    frames: bool,
+}
+
+impl Args {
+    fn matches(&self, path: &Path) -> bool {
+        if self.exact {
+            let name = path.file_name().unwrap().to_string_lossy();
+            self.filter.iter().any(|v| v == &name)
+        } else {
+            let path = path.to_string_lossy();
+            self.filter.is_empty() || self.filter.iter().any(|v| path.contains(v))
+        }
+    }
+}
+
+fn main() {
+    let args = Args::parse();
+    let mut filtered = Vec::new();
     // Since different tests can affect each other through the memoization
     // cache, a deterministic order is important for reproducibility.
     for entry in WalkDir::new("typ").sort_by_file_name() {
@@ -78,14 +120,9 @@ fn main() {
         let pdf_path =
             args.pdf.then(|| Path::new(PDF_DIR).join(path).with_extension("pdf"));
 
-        ok += test(
+        ok +=
-            &mut world,
+            test(&mut world, &src_path, &png_path, &ref_path, pdf_path.as_deref(), &args)
-            &src_path,
+                as usize;
-            &png_path,
-            &ref_path,
-            pdf_path.as_deref(),
-            args.update,
-        ) as usize;
     }
 
     if len > 1 {
@@ -104,66 +141,6 @@ fn main() {
     }
 }
 
-/// Parsed command line arguments.
-struct Args {
-    filter: Vec<String>,
-    exact: bool,
-    pdf: bool,
-    update: bool,
-    print: PrintConfig,
-}
-
-/// Which things to print out for debugging.
-#[derive(Default, Copy, Clone, Eq, PartialEq)]
-struct PrintConfig {
-    syntax: bool,
-    model: bool,
-    frames: bool,
-}
-
-impl Args {
-    fn new(args: impl Iterator<Item = String>) -> Self {
-        let mut filter = Vec::new();
-        let mut exact = false;
-        let mut pdf = false;
-        let mut update = env::var_os("UPDATE_EXPECT").is_some();
-        let mut print = PrintConfig::default();
-
-        for arg in args {
-            match arg.as_str() {
-                // Ignore this, its for cargo.
-                "--nocapture" => {}
-                // Match only the exact filename.
-                "--exact" => exact = true,
-                // Generate PDFs.
-                "--pdf" => pdf = true,
-                // Update the reference images.
-                "--update" => update = true,
-                // Debug print the syntax trees.
-                "--syntax" => print.syntax = true,
-                // Debug print the model.
-                "--model" => print.model = true,
-                // Debug print the frames.
-                "--frames" => print.frames = true,
-                // Everything else is a file filter.
-                _ => filter.push(arg),
-            }
-        }
-
-        Self { filter, exact, pdf, update, print }
-    }
-
-    fn matches(&self, path: &Path) -> bool {
-        if self.exact {
-            let name = path.file_name().unwrap().to_string_lossy();
-            self.filter.iter().any(|v| v == &name)
-        } else {
-            let path = path.to_string_lossy();
-            self.filter.is_empty() || self.filter.iter().any(|v| path.contains(v))
-        }
-    }
-}
-
 fn library() -> Library {
     /// Display: Test
     /// Category: test
@@ -357,7 +334,7 @@ fn test(
     png_path: &Path,
     ref_path: &Path,
     pdf_path: Option<&Path>,
-    update: bool,
+    args: &Args,
 ) -> bool {
     let name = src_path.strip_prefix(TYP_DIR).unwrap_or(src_path);
     println!("Testing {}", name.display());
@@ -374,6 +351,12 @@ fn test(
 
     let parts: Vec<_> = text.split("\n---").collect();
     for (i, &part) in parts.iter().enumerate() {
+        if let Some(x) = args.subtest {
+            if x != i {
+                println!("skipped subtest {i}");
+                continue;
+            }
+        }
         let is_header = i == 0
             && parts.len() > 1
             && part
@@ -424,7 +407,7 @@ fn test(
                     .zip(ref_pixmap.data())
                     .any(|(&a, &b)| a.abs_diff(b) > 2)
             {
-                if update {
+                if args.update {
                     update_image(png_path, ref_path);
                     updated = true;
                 } else {
@@ -433,7 +416,7 @@ fn test(
                 }
             }
         } else if !document.pages.is_empty() {
-            if update {
+            if args.update {
                 update_image(png_path, ref_path);
                 updated = true;
             } else {