feat(cli/test): deno test --clean (#23519)

The result of the call is ignored as it throws even when the directory
does not exist.

Closes #23491

cli/args/flags.rs

@@ -333,6 +333,7 @@ pub struct TestFlags {
   pub doc: bool,
   pub no_run: bool,
   pub coverage_dir: Option<String>,
+  pub clean: bool,
   pub fail_fast: Option<NonZeroUsize>,
   pub files: FileFlags,
   pub allow_none: bool,
@@ -2630,6 +2631,14 @@ Directory arguments are expanded to all contained files matching the glob
         .conflicts_with("inspect-brk")
         .help("Collect coverage profile data into DIR. If DIR is not specified, it uses 'coverage/'."),
     )
+    .arg(
+      Arg::new("clean")
+        .long("clean")
+        .help("Empty the temporary coverage profile data directory before running tests.
+        
+Note: running multiple `deno test --clean` calls in series or parallel for the same coverage directory may cause race conditions.")
+        .action(ArgAction::SetTrue),
+    )
     .arg(
       Arg::new("parallel")
         .long("parallel")
@@ -4240,6 +4249,7 @@ fn test_parse(flags: &mut Flags, matches: &mut ArgMatches) {
   let doc = matches.get_flag("doc");
   let allow_none = matches.get_flag("allow-none");
   let filter = matches.remove_one::<String>("filter");
+  let clean = matches.get_flag("clean");
 
   let fail_fast = if matches.contains_id("fail-fast") {
     Some(
@@ -4325,6 +4335,7 @@ fn test_parse(flags: &mut Flags, matches: &mut ArgMatches) {
     no_run,
     doc,
     coverage_dir: matches.remove_one::<String>("coverage"),
+    clean,
     fail_fast,
     files: FileFlags { include, ignore },
     filter,
@@ -8189,7 +8200,7 @@ mod tests {
   #[test]
   fn test_with_flags() {
     #[rustfmt::skip]
-    let r = flags_from_vec(svec!["deno", "test", "--unstable", "--no-npm", "--no-remote", "--trace-leaks", "--no-run", "--filter", "- foo", "--coverage=cov", "--location", "https:foo", "--allow-net", "--allow-none", "dir1/", "dir2/", "--", "arg1", "arg2"]);
+    let r = flags_from_vec(svec!["deno", "test", "--unstable", "--no-npm", "--no-remote", "--trace-leaks", "--no-run", "--filter", "- foo", "--coverage=cov", "--clean", "--location", "https:foo", "--allow-net", "--allow-none", "dir1/", "dir2/", "--", "arg1", "arg2"]);
     assert_eq!(
       r.unwrap(),
       Flags {
@@ -8207,6 +8218,7 @@ mod tests {
           concurrent_jobs: None,
           trace_leaks: true,
           coverage_dir: Some("cov".to_string()),
+          clean: true,
           watch: Default::default(),
           reporter: Default::default(),
           junit_path: None,
@@ -8294,6 +8306,7 @@ mod tests {
           concurrent_jobs: Some(NonZeroUsize::new(4).unwrap()),
           trace_leaks: false,
           coverage_dir: None,
+          clean: false,
           watch: Default::default(),
           junit_path: None,
         }),
@@ -8330,6 +8343,7 @@ mod tests {
           concurrent_jobs: None,
           trace_leaks: false,
           coverage_dir: None,
+          clean: false,
           watch: Default::default(),
           reporter: Default::default(),
           junit_path: None,
@@ -8371,6 +8385,7 @@ mod tests {
           concurrent_jobs: None,
           trace_leaks: false,
           coverage_dir: None,
+          clean: false,
           watch: Default::default(),
           reporter: Default::default(),
           junit_path: None,
@@ -8506,6 +8521,7 @@ mod tests {
           concurrent_jobs: None,
           trace_leaks: false,
           coverage_dir: None,
+          clean: false,
           watch: Default::default(),
           reporter: Default::default(),
           junit_path: None,
@@ -8540,6 +8556,7 @@ mod tests {
           concurrent_jobs: None,
           trace_leaks: false,
           coverage_dir: None,
+          clean: false,
           watch: Some(Default::default()),
           reporter: Default::default(),
           junit_path: None,
@@ -8573,6 +8590,7 @@ mod tests {
           concurrent_jobs: None,
           trace_leaks: false,
           coverage_dir: None,
+          clean: false,
           watch: Some(Default::default()),
           reporter: Default::default(),
           junit_path: None,
@@ -8608,6 +8626,7 @@ mod tests {
           concurrent_jobs: None,
           trace_leaks: false,
           coverage_dir: None,
+          clean: false,
           watch: Some(WatchFlags {
             hmr: false,
             no_clear_screen: true,

cli/main.rs

@@ -191,6 +191,9 @@ async fn run_subcommand(flags: Flags) -> Result<i32, AnyError> {
     DenoSubcommand::Test(test_flags) => {
       spawn_subcommand(async {
         if let Some(ref coverage_dir) = test_flags.coverage_dir {
+          if test_flags.clean {
+            let _ = std::fs::remove_dir_all(coverage_dir);
+          }
           std::fs::create_dir_all(coverage_dir)
             .with_context(|| format!("Failed creating: {coverage_dir}"))?;
           // this is set in order to ensure spawned processes use the same

tests/specs/test/clean_flag/__test__.jsonc

@@ -0,0 +1,5 @@
+{
+  "args": "run -A main.js",
+  "exitCode": 0,
+  "output": "main.out"
+}

tests/specs/test/clean_flag/main.js

@@ -0,0 +1,23 @@
+import { emptyDir } from "../../../util/std/fs/empty_dir.ts";
+
+const DIR = "./coverage";
+const COMMAND = new Deno.Command(Deno.execPath(), {
+  args: ["test", "--coverage", "--clean"],
+  stdout: "null",
+});
+
+async function getCoverageFiles() {
+  return await Array.fromAsync(Deno.readDir(DIR), ({ name }) => name);
+}
+
+await emptyDir(DIR);
+await COMMAND.output();
+const files1 = new Set(await getCoverageFiles());
+
+await COMMAND.output();
+const files2 = new Set(await getCoverageFiles());
+
+console.log(files1.size === files2.size);
+console.log(files1.intersection(files2).size === 0);
+await emptyDir(DIR);
+await Deno.remove(DIR);

tests/specs/test/clean_flag/main.out

@@ -0,0 +1,2 @@
+true
+true

tests/specs/test/clean_flag/sum.js

@@ -0,0 +1,3 @@
+export function sum(a, b) {
+  return a + b;
+}

tests/specs/test/clean_flag/sum_test.js

@@ -0,0 +1,6 @@
+import { sum } from "./sum.js";
+import { assertEquals } from "../../../util/std/assert/assert_equals.ts";
+
+Deno.test("sum()", () => {
+  assertEquals(sum(1, 2), 3);
+});