Add --list argument to `wasm-bindgen-test-runner

CHANGELOG.md

@@ -14,6 +14,9 @@
 * Support importing memory and using `wasm_bindgen::module()` in Node.js.
   [#4349](https://github.com/rustwasm/wasm-bindgen/pull/4349)
 
+* Add `--list` argument to `wasm-bindgen-test-runner`.
+  [#4356](https://github.com/rustwasm/wasm-bindgen/pull/4356)
+
 ### Changed
 
 * Optional parameters are now typed as `T | undefined | null` to reflect the actual JS behavior.

crates/cli/src/bin/wasm-bindgen-test-runner/main.rs

@@ -13,6 +13,7 @@
 
 use anyhow::{anyhow, bail, Context};
 use clap::Parser;
+use clap::ValueEnum;
 use log::error;
 use std::env;
 use std::fs;
@@ -43,6 +44,17 @@ struct Cli {
         help = "Skip tests whose names contain FILTER (this flag can be used multiple times)"
     )]
     skip: Vec<String>,
+    /// Only list all tests and benchmarks.
+    #[arg(long = "list", help = "List all tests and benchmarks")]
+    list: bool,
+    /// Specifies the format of the output.
+    #[arg(
+        long = "format",
+        value_enum,
+        value_name = "terse",
+        help = "Configure formatting of output"
+    )]
+    format: Option<FormatSetting>,
     #[arg(
         index = 2,
         value_name = "FILTER",
@@ -86,6 +98,28 @@ fn main() -> anyhow::Result<()> {
         .and_then(|s| s.to_str())
         .context("file to test is not a valid file, can't extract file name")?;
 
+    // Collect all tests that the test harness is supposed to run. We assume
+    // that any exported function with the prefix `__wbg_test` is a test we need
+    // to execute.
+    let wasm = fs::read(&cli.file).context("failed to read Wasm file")?;
+    let mut wasm =
+        walrus::Module::from_buffer(&wasm).context("failed to deserialize Wasm module")?;
+    let mut tests = Vec::new();
+
+    for export in wasm.exports.iter() {
+        if export.name.starts_with("__wbgt_") {
+            tests.push(export.name.to_string());
+        }
+    }
+
+    if cli.list {
+        for test in tests {
+            println!("{}: test", test.split_once("::").unwrap().1);
+        }
+
+        return Ok(());
+    }
+
     // wasm_file_to_test may be
     // - a cargo-like directory layout and generate output at
     //      `target/wasm32-unknown-unknown/...`
@@ -112,21 +146,6 @@ fn main() -> anyhow::Result<()> {
 
     let module = "wasm-bindgen-test";
 
-    // Collect all tests that the test harness is supposed to run. We assume
-    // that any exported function with the prefix `__wbg_test` is a test we need
-    // to execute.
-    let wasm = fs::read(&cli.file).context("failed to read Wasm file")?;
-    let mut wasm =
-        walrus::Module::from_buffer(&wasm).context("failed to deserialize Wasm module")?;
-    let mut tests = Vec::new();
-
-    for export in wasm.exports.iter() {
-        if !export.name.starts_with("__wbgt_") {
-            continue;
-        }
-        tests.push(export.name.to_string());
-    }
-
     // Right now there's a bug where if no tests are present then the
     // `wasm-bindgen-test` runtime support isn't linked in, so just bail out
     // early saying everything is ok.
@@ -386,3 +405,10 @@ fn coverage_args(tmpdir: &Path) -> PathBuf {
         None => PathBuf::from(generated(tmpdir, &prefix)),
     }
 }
+
+/// Possible values for the `--format` option.
+#[derive(Debug, Clone, Copy, ValueEnum)]
+enum FormatSetting {
+    /// Display one character per test
+    Terse,
+}

crates/test-macro/src/lib.rs

@@ -4,12 +4,8 @@
 extern crate proc_macro;
 
 use proc_macro2::*;
-use quote::format_ident;
 use quote::quote;
 use quote::quote_spanned;
-use std::sync::atomic::*;
-
-static CNT: AtomicUsize = AtomicUsize::new(0);
 
 #[proc_macro_attribute]
 pub fn wasm_bindgen_test(
@@ -94,18 +90,14 @@ pub fn wasm_bindgen_test(
         quote! { cx.execute_sync(test_name, #ident, #should_panic_par, #ignore); }
     };
 
-    // We generate a `#[no_mangle]` with a known prefix so the test harness can
-    // later slurp up all of these functions and pass them as arguments to the
-    // main test harness. This is the entry point for all tests.
-    let name = format_ident!("__wbgt_{}_{}", ident, CNT.fetch_add(1, Ordering::SeqCst));
     let wasm_bindgen_path = attributes.wasm_bindgen_path;
     tokens.extend(
         quote! {
             const _: () = {
                 #wasm_bindgen_path::__rt::wasm_bindgen::__wbindgen_coverage! {
-                #[no_mangle]
+                #[export_name = concat!("__wbgt_", ::core::module_path!(), "::", ::core::stringify!(#ident))]
                 #[cfg(all(target_arch = "wasm32", any(target_os = "unknown", target_os = "none")))]
-                pub extern "C" fn #name(cx: &#wasm_bindgen_path::__rt::Context) {
+                extern "C" fn __wbgt_test(cx: &#wasm_bindgen_path::__rt::Context) {
                     let test_name = ::core::concat!(::core::module_path!(), "::", ::core::stringify!(#ident));
                     #test_body
                 }