2. Allow compiling test-runner with only typst_syntax

Cargo.lock

@@ -3018,6 +3018,7 @@ dependencies = [
  "typst-pdf",
  "typst-render",
  "typst-svg",
+ "typst-syntax",
  "unscanny",
  "walkdir",
 ]

tests/Cargo.toml

@@ -11,14 +11,32 @@ name = "tests"
 path = "src/tests.rs"
 harness = false
 
+[features]
+# Allow just compiling the parser when only testing typst-syntax. To do so,
+# pass '--no-default-features' to 'cargo test'.
+default = [
+    # "typst-syntax" intentionally not present
+    "typst",
+    "typst-assets",
+    "typst-dev-assets",
+    "typst-library",
+    "typst-pdf",
+    "typst-render",
+    "typst-svg",
+    "typst-svg",
+]
+
 [dependencies]
-typst = { workspace = true }
-typst-assets = { workspace = true, features = ["fonts"] }
-typst-dev-assets = { workspace = true }
-typst-library = { workspace = true }
-typst-pdf = { workspace = true }
-typst-render = { workspace = true }
-typst-svg = { workspace = true }
+typst-syntax = { workspace = true }
+# Mark other Typst crates as optional so we can use '--no-default-features'
+# to decrease compile times for parser testing.
+typst = { workspace = true, optional = true }
+typst-assets = { workspace = true, features = ["fonts"], optional = true }
+typst-dev-assets = { workspace = true, optional = true }
+typst-library = { workspace = true, optional = true }
+typst-pdf = { workspace = true, optional = true }
+typst-render = { workspace = true, optional = true }
+typst-svg = { workspace = true, optional = true }
 clap = { workspace = true }
 comemo = { workspace = true }
 ecow = { workspace = true }

tests/src/args.rs

@@ -66,6 +66,10 @@ pub struct CliArguments {
     /// This overrides the normal testing system. It parses, but does not run
     /// the test suite.
     ///
+    /// If `cargo test` is run with `--no-default-features`, then compiling will
+    /// not include Typst's core crates, only typst-syntax, greatly speeding up
+    /// debugging when changing the parser.
+    ///
     /// You can generate a correct reference directory by running on a known
     /// good commit and copying the generated outputs to a new directory.
     /// `_things` may be a good location as it is in the top-level gitignore.

tests/src/collect.rs

@@ -6,8 +6,8 @@ use std::str::FromStr;
 use std::sync::LazyLock;
 
 use ecow::{eco_format, EcoString};
-use typst::syntax::package::PackageVersion;
-use typst::syntax::{is_id_continue, is_ident, is_newline, FileId, Source, VirtualPath};
+use typst_syntax::package::PackageVersion;
+use typst_syntax::{is_id_continue, is_ident, is_newline, FileId, Source, VirtualPath};
 use unscanny::Scanner;
 
 /// Collects all tests from all files.

tests/src/logger.rs

@@ -2,7 +2,16 @@ use std::io::{self, IsTerminal, StderrLock, Write};
 use std::time::{Duration, Instant};
 
 use crate::collect::Test;
-use crate::run::TestResult;
+
+/// The result of running a single test.
+pub struct TestResult {
+    /// The error log for this test. If empty, the test passed.
+    pub errors: String,
+    /// The info log for this test.
+    pub infos: String,
+    /// Whether the image was mismatched.
+    pub mismatched_image: bool,
+}
 
 /// Receives status updates by individual test runs.
 pub struct Logger<'a> {
@@ -58,7 +67,7 @@ impl<'a> Logger<'a> {
             }
         };
 
-        if result.is_ok() {
+        if result.errors.is_empty() {
             self.passed += 1;
         } else {
             self.failed += 1;

tests/src/run.rs

@@ -12,6 +12,7 @@ use typst::WorldExt;
 use typst_pdf::PdfOptions;
 
 use crate::collect::{FileSize, NoteKind, Test};
+use crate::logger::TestResult;
 use crate::world::TestWorld;
 
 /// Runs a single test.
@@ -21,23 +22,6 @@ pub fn run(test: &Test) -> TestResult {
     Runner::new(test).run()
 }
 
-/// The result of running a single test.
-pub struct TestResult {
-    /// The error log for this test. If empty, the test passed.
-    pub errors: String,
-    /// The info log for this test.
-    pub infos: String,
-    /// Whether the image was mismatched.
-    pub mismatched_image: bool,
-}
-
-impl TestResult {
-    /// Whether the test passed.
-    pub fn is_ok(&self) -> bool {
-        self.errors.is_empty()
-    }
-}
-
 /// Write a line to a log sink, defaulting to the test's error log.
 macro_rules! log {
     (into: $sink:expr, $($tts:tt)*) => {

tests/src/tests.rs

@@ -1,10 +1,16 @@
 //! Typst's test runner.
 
+#![cfg_attr(not(feature = "default"), allow(dead_code, unused_imports))]
+
 mod args;
 mod collect;
-mod custom;
 mod logger;
+
+#[cfg(feature = "default")]
+mod custom;
+#[cfg(feature = "default")]
 mod run;
+#[cfg(feature = "default")]
 mod world;
 
 use std::path::{Path, PathBuf};
@@ -17,8 +23,7 @@ use rayon::iter::{ParallelBridge, ParallelIterator};
 
 use crate::args::{CliArguments, Command};
 use crate::collect::Test;
-use crate::logger::Logger;
-use crate::run::TestResult;
+use crate::logger::{Logger, TestResult};
 
 /// The parsed command line arguments.
 static ARGS: LazyLock<CliArguments> = LazyLock::new(CliArguments::parse);
@@ -95,12 +100,17 @@ fn test() {
     }
 
     let parser_dirs = ARGS.parser_compare.clone().map(create_syntax_store);
+    #[cfg(not(feature = "default"))]
+    let parser_dirs = parser_dirs.or_else(|| Some(create_syntax_store(None)));
 
     let runner = |test: &Test| {
         if let Some((live_path, ref_path)) = &parser_dirs {
             run_parser_test(test, live_path, ref_path)
         } else {
-            run::run(test)
+            #[cfg(feature = "default")]
+            return run::run(test);
+            #[cfg(not(feature = "default"))]
+            unreachable!();
         }
     };