Testsuite: decrease length001 timeout for JS (#22921)

2 files changed, 8 insertions, 3 deletions

diff --git a/libraries/base/tests/all.T b/libraries/base/tests/all.T
index 01f4094c6f..f3a97448d5 100644
--- a/libraries/base/tests/all.T
+++ b/libraries/base/tests/all.T
@@ -79,7 +79,9 @@ test('length001',
      # excessive amounts of stack space. So we specifically set a low
      # stack limit and mark it as failing under a few conditions.
      [extra_run_opts('+RTS -K8m -RTS'),
-     expect_fail_for(['normal', 'threaded1', 'llvm', 'nonmoving', 'nonmoving_thr', 'nonmoving_thr_ghc'])],
+     expect_fail_for(['normal', 'threaded1', 'llvm', 'nonmoving', 'nonmoving_thr', 'nonmoving_thr_ghc']),
+     # JS doesn't support stack limit so the test sometimes passes just fine. We decrease the timeout duration to force the failure.
+     when(js_arch(), run_timeout_multiplier(0.2))],
      compile_and_run, [''])
 
 test('ratio001', 	normal, compile_and_run, [''])
diff --git a/testsuite/driver/testlib.py b/testsuite/driver/testlib.py
index 1c5f5fcaf7..c35bea1811 100644
--- a/testsuite/driver/testlib.py
+++ b/testsuite/driver/testlib.py
@@ -129,14 +129,17 @@ def no_deps( name, opts):
 def skip( name, opts ):
     opts.skip = True
 
+def js_arch() -> bool:
+    return arch("javascript");
+
 # disable test on JS arch
 def js_skip( name, opts ):
-    if arch("javascript"):
+    if js_arch():
         skip(name,opts)
 
 # expect broken for the JS backend
 def js_broken( bug: IssueNumber ):
-    if arch("javascript"):
+    if js_arch():
         return expect_broken(bug);
     else:
         return normal;