Fix running emrun tests on Linux against the Linux system browser

emrun.py

@@ -1768,7 +1768,7 @@ def run(args):  # noqa: C901, PLR0912, PLR0915
       if browser_exe == 'cmd':
         url = url.replace('&', '^&')
       url = url.replace('0.0.0.0', 'localhost')
-      browser += browser_args + [url]
+      browser += browser_args
 
   if options.kill_start:
     pname = processname_killed_atexit
@@ -1801,6 +1801,14 @@ def run(cmd):
 
     browser += ['-no-remote', '--profile', profile_dir.replace('\\', '/')]
 
+  # Pass the URL to open as the very last item on the command line, and use the -url xxx parameter
+  # to open the url to work around https://bugzil.la/1996614.
+  if browser_exe and not options.android:
+    if 'firefox' in browser_exe:
+      browser += ['-url', url]
+    else:
+      browser += [url]
+
   if options.system_info:
     logi('Time of run: ' + time.strftime("%x %X"))
     logi(get_system_info(format_json=options.json))

test/browser_common.py

@@ -10,6 +10,7 @@
 import queue
 import re
 import shlex
+import shutil
 import subprocess
 import threading
 import time
@@ -35,9 +36,9 @@
 )
 
 from tools import feature_matrix, utils
-from tools.feature_matrix import UNSUPPORTED
+from tools.feature_matrix import OLDEST_SUPPORTED_FIREFOX, UNSUPPORTED
 from tools.shared import DEBUG, EMCC, exit_with_error
-from tools.utils import MACOS, WINDOWS, memoize, path_from_root, read_binary
+from tools.utils import LINUX, MACOS, WINDOWS, memoize, path_from_root, read_binary
 
 logger = logging.getLogger('common')
 
@@ -165,8 +166,22 @@ def get_safari_version():
 def get_firefox_version():
   if not is_firefox():
     return UNSUPPORTED
-  exe_path = shlex.split(EMTEST_BROWSER)[0]
+  exe_path = shutil.which(shlex.split(EMTEST_BROWSER)[0])
   ini_path = os.path.join(os.path.dirname(exe_path), '../Resources/platform.ini' if MACOS else 'platform.ini')
+  # On Linux, Firefox system installation uses a specific directory structure,
+  # where platform.ini is not located in same directory as the browser executable.
+  if LINUX and exe_path.startswith('/usr/bin/'):
+    def find_system_firefox_platform_ini():
+      for path in ['/usr/lib/firefox-esr/', '/usr/lib/firefox/']:
+        ini = os.path.join(path, 'platform.ini')
+        if os.path.isfile(ini):
+          return ini
+
+    ini_path = find_system_firefox_platform_ini()
+    if not ini_path:
+      logger.warning(f'Firefox browser detected in {EMTEST_BROWSER}, but could not find Firefox platform.ini to detect Firefox version. Assuming OLDEST_SUPPORTED_FIREFOX={OLDEST_SUPPORTED_FIREFOX}')
+      return OLDEST_SUPPORTED_FIREFOX
+
   # Extract the first numeric part before any dot (e.g. "Milestone=102.15.1" → 102)
   m = re.search(r"^Milestone=(.*)$", read_file(ini_path), re.MULTILINE)
   milestone = m.group(1).strip()
@@ -319,6 +334,11 @@ def configure_test_browser():
 
   if not EMTEST_BROWSER:
     EMTEST_BROWSER = 'google-chrome'
+    if not shutil.which(EMTEST_BROWSER):
+      EMTEST_BROWSER = 'firefox'
+      if not shutil.which(EMTEST_BROWSER):
+        # FIXME: This should really be and error, but this code currently also runs for non-browser tests.
+        EMTEST_BROWSER = 'default-browser-not-found'
 
   if WINDOWS and '"' not in EMTEST_BROWSER and "'" not in EMTEST_BROWSER:
     # On Windows env. vars canonically use backslashes as directory delimiters, e.g.

test/runner.py

@@ -372,7 +372,7 @@ def sort_tests_failing_and_slowest_first_comparator(x, y):
 
 
 def use_parallel_suite(module):
-  suite_supported = module.__name__ not in {'test_sanity', 'test_benchmark', 'test_sockets', 'test_interactive', 'test_stress'}
+  suite_supported = module.__name__ not in {'test_sanity', 'test_benchmark', 'test_sockets', 'test_interactive', 'test_stress', 'test_emrun'}
   if not common.EMTEST_SAVE_DIR and not shared.DEBUG:
     has_multiple_cores = parallel_testsuite.num_cores() > 1
     if suite_supported and has_multiple_cores:

test/test_browser.py

@@ -3,11 +3,9 @@
 # University of Illinois/NCSA Open Source License.  Both these licenses can be
 # found in the LICENSE file.
 
-import argparse
 import os
 import random
 import re
-import shlex
 import shutil
 import struct
 import subprocess
@@ -33,15 +31,12 @@
   find_browser_test_file,
   get_browser,
   get_safari_version,
-  has_browser,
   is_chrome,
   is_firefox,
   is_safari,
 )
 from common import (
-  EMRUN,
   WEBIDL_BINDER,
-  RunnerCore,
   copy_asset,
   copytree,
   create_file,
@@ -73,7 +68,7 @@
 from tools import ports, shared, utils
 from tools.feature_matrix import Feature
 from tools.link import binary_encode
-from tools.shared import EMCC, FILE_PACKAGER, PIPE
+from tools.shared import EMCC, FILE_PACKAGER
 from tools.utils import WINDOWS, delete_dir, write_binary, write_file
 
 
@@ -5708,123 +5703,6 @@ def test_shell_minimal(self, args):
     self.btest_exit('browser_test_hello_world.c', cflags=['--shell-file', path_from_root('html/shell_minimal.html')] + args)
 
 
-class emrun(RunnerCore):
-  def test_emrun_info(self):
-    if not has_browser():
-      self.skipTest('need a browser')
-    result = self.run_process([EMRUN, '--system-info', '--browser_info'], stdout=PIPE).stdout
-    assert 'CPU' in result
-    assert 'Browser' in result
-    assert 'Traceback' not in result
-
-    result = self.run_process([EMRUN, '--list-browsers'], stdout=PIPE).stdout
-    assert 'Traceback' not in result
-
-  def test_no_browser(self):
-    # Test --no-browser mode where we have to take care of launching the browser ourselves
-    # and then killing emrun when we are done.
-    if not has_browser():
-      self.skipTest('need a browser')
-
-    self.run_process([EMCC, test_file('test_emrun.c'), '--emrun', '-o', 'hello_world.html'])
-    proc = subprocess.Popen([EMRUN, '--no-browser', '.', '--port=3333'], stdout=PIPE)
-    try:
-      if get_browser():
-        url = 'http://localhost:3333/hello_world.html?argv0'
-        print(f'Starting browser to {url}')
-        BrowserCore.browser_open(url)
-        try:
-          while True:
-            stdout = proc.stdout.read()
-            if b'Dumping out file' in stdout:
-              break
-        finally:
-          print('Terminating browser')
-          BrowserCore.browser_terminate()
-    finally:
-      print('Terminating emrun server')
-      proc.terminate()
-      proc.wait()
-
-  def test_program_arg_separator(self):
-    # Verify that trying to pass argument to the page without the `--` separator will
-    # generate an actionable error message
-    err = self.expect_fail([EMRUN, '--foo'])
-    self.assertContained('error: unrecognized arguments: --foo', err)
-    self.assertContained('remember to add `--` between arguments', err)
-
-  @also_with_threads
-  def test_emrun(self):
-    self.emcc('test_emrun.c', ['--emrun', '-o', 'test_emrun.html'])
-    if not has_browser():
-      self.skipTest('need a browser')
-
-    # We cannot run emrun from the temp directory the suite will clean up afterwards, since the
-    # browser that is launched will have that directory as startup directory, and the browser will
-    # not close as part of the test, pinning down the cwd on Windows and it wouldn't be possible to
-    # delete it. Therefore switch away from that directory before launching.
-    os.chdir(path_from_root())
-
-    # emrun tests may run in parallel processes, so each test case should use a unique port number
-    # to avoid port address already in use errors.
-    port = '6939'
-    if '-pthread' in self.cflags:
-      port = '6940'
-
-    args_base = [EMRUN, '--timeout', '30', '--safe_firefox_profile',
-                 '--kill-exit', '--port', port, '--verbose',
-                 '--log-stdout', self.in_dir('stdout.txt'),
-                 '--log-stderr', self.in_dir('stderr.txt')]
-
-    if get_browser() is not None:
-      # If EMTEST_BROWSER carried command line arguments to pass to the browser,
-      # (e.g. "firefox -profile /path/to/foo") those can't be passed via emrun,
-      # so strip them out.
-      browser_cmd = shlex.split(get_browser())
-      browser_path = browser_cmd[0]
-      args_base += ['--browser', browser_path]
-      if len(browser_cmd) > 1:
-        browser_args = browser_cmd[1:]
-        if 'firefox' in browser_path and ('-profile' in browser_args or '--profile' in browser_args):
-          # emrun uses its own -profile, strip it out
-          parser = argparse.ArgumentParser(add_help=False) # otherwise it throws with -headless
-          parser.add_argument('-profile')
-          parser.add_argument('--profile')
-          browser_args = parser.parse_known_args(browser_args)[1]
-        if browser_args:
-          args_base += ['--browser_args', ' ' + ' '.join(browser_args)]
-
-    for args in [
-        [],
-        ['--port', '0'],
-        ['--private_browsing'],
-        ['--dump_out_directory', 'other dir/multiple'],
-        ['--dump_out_directory=foo_bar'],
-    ]:
-      args = args_base + args + [self.in_dir('test_emrun.html'), '--', '1', '2', '--3', 'escaped space', 'with_underscore']
-      print(shlex.join(args))
-      proc = self.run_process(args, check=False)
-      self.assertEqual(proc.returncode, 100)
-      dump_dir = 'dump_out'
-      if '--dump_out_directory' in args:
-        dump_dir = 'other dir/multiple'
-      elif '--dump_out_directory=foo_bar' in args:
-        dump_dir = 'foo_bar'
-      self.assertExists(self.in_dir(f'{dump_dir}/test.dat'))
-      self.assertExists(self.in_dir(f'{dump_dir}/heap.dat'))
-      self.assertExists(self.in_dir(f'{dump_dir}/nested/with space.dat'))
-      stdout = read_file(self.in_dir('stdout.txt'))
-      stderr = read_file(self.in_dir('stderr.txt'))
-      self.assertContained('argc: 6', stdout)
-      self.assertContained('argv[3]: --3', stdout)
-      self.assertContained('argv[4]: escaped space', stdout)
-      self.assertContained('argv[5]: with_underscore', stdout)
-      self.assertContained('Hello, world!', stdout)
-      self.assertContained('Testing ASCII characters: !"$%&\'()*+,-./:;<=>?@[\\]^_`{|}~', stdout)
-      self.assertContained('Testing char sequences: %20%21 &auml;', stdout)
-      self.assertContained('hello, error stream!', stderr)
-
-
 class browser64(browser):
   def setUp(self):
     super().setUp()

test/test_emrun.py

@@ -0,0 +1,132 @@
+# Copyright 2026 The Emscripten Authors.  All rights reserved.
+# Emscripten is available under two separate licenses, the MIT license and the
+# University of Illinois/NCSA Open Source License.  Both these licenses can be
+# found in the LICENSE file.
+
+import argparse
+import os
+import shlex
+import subprocess
+
+from browser_common import BrowserCore, get_browser, has_browser
+from common import EMRUN, RunnerCore, path_from_root, read_file, test_file
+from test_browser import also_with_threads
+
+from tools.shared import EMCC, PIPE
+
+
+class emrun(RunnerCore):
+  def test_emrun_info(self):
+    if not has_browser():
+      self.skipTest('need a browser')
+    result = self.run_process([EMRUN, '--system-info', '--browser_info'], stdout=PIPE).stdout
+    assert 'CPU' in result
+    assert 'Browser' in result
+    assert 'Traceback' not in result
+
+    result = self.run_process([EMRUN, '--list-browsers'], stdout=PIPE).stdout
+    assert 'Traceback' not in result
+
+  def test_no_browser(self):
+    # Test --no-browser mode where we have to take care of launching the browser ourselves
+    # and then killing emrun when we are done.
+    if not has_browser():
+      self.skipTest('need a browser')
+
+    self.run_process([EMCC, test_file('test_emrun.c'), '--emrun', '-o', 'hello_world.html'])
+    proc = subprocess.Popen([EMRUN, '--no-browser', '.', '--port=3333'], stdout=PIPE)
+    try:
+      if get_browser():
+        url = 'http://localhost:3333/hello_world.html?argv0'
+        print(f'Starting browser to {url}')
+        BrowserCore.browser_open(url)
+        try:
+          while True:
+            stdout = proc.stdout.read()
+            if b'Dumping out file' in stdout:
+              break
+        finally:
+          print('Terminating browser')
+          BrowserCore.browser_terminate()
+    finally:
+      print('Terminating emrun server')
+      proc.terminate()
+      proc.wait()
+
+  def test_program_arg_separator(self):
+    # Verify that trying to pass argument to the page without the `--` separator will
+    # generate an actionable error message
+    err = self.expect_fail([EMRUN, '--foo'])
+    self.assertContained('error: unrecognized arguments: --foo', err)
+    self.assertContained('remember to add `--` between arguments', err)
+
+  @also_with_threads
+  def test_emrun(self):
+    self.emcc('test_emrun.c', ['--emrun', '-o', 'test_emrun.html'])
+    if not has_browser():
+      self.skipTest('need a browser')
+
+    # We cannot run emrun from the temp directory the suite will clean up afterwards, since the
+    # browser that is launched will have that directory as startup directory, and the browser will
+    # not close as part of the test, pinning down the cwd on Windows and it wouldn't be possible to
+    # delete it. Therefore switch away from that directory before launching.
+    os.chdir(path_from_root())
+
+    # emrun tests may run in parallel processes, so each test case should use a unique port number
+    # to avoid port address already in use errors.
+    port = '6939'
+    if '-pthread' in self.cflags:
+      port = '6940'
+
+    args_base = [EMRUN, '--timeout', '30', '--safe_firefox_profile',
+                 '--kill-exit', '--port', port, '--verbose',
+                 '--log-stdout', self.in_dir('stdout.txt'),
+                 '--log-stderr', self.in_dir('stderr.txt')]
+
+    if get_browser() is not None:
+      # If EMTEST_BROWSER carried command line arguments to pass to the browser,
+      # (e.g. "firefox -profile /path/to/foo") those can't be passed via emrun,
+      # so strip them out.
+      browser_cmd = shlex.split(get_browser())
+      browser_path = browser_cmd[0]
+      args_base += ['--browser', browser_path]
+      if len(browser_cmd) > 1:
+        browser_args = browser_cmd[1:]
+        if 'firefox' in browser_path and ('-profile' in browser_args or '--profile' in browser_args):
+          # emrun uses its own -profile, strip it out
+          parser = argparse.ArgumentParser(add_help=False) # otherwise it throws with -headless
+          parser.add_argument('-profile')
+          parser.add_argument('--profile')
+          browser_args = parser.parse_known_args(browser_args)[1]
+        if browser_args:
+          args_base += ['--browser_args', ' ' + ' '.join(browser_args)]
+
+    for args in [
+        [],
+        ['--port', '0'],
+        ['--private_browsing'],
+        ['--dump_out_directory', 'other dir/multiple'],
+        ['--dump_out_directory=foo_bar'],
+    ]:
+      args = args_base + args + [self.in_dir('test_emrun.html'), '--', '1', '2', '--3', 'escaped space', 'with_underscore']
+      print(shlex.join(args))
+      proc = self.run_process(args, check=False)
+      self.assertEqual(proc.returncode, 100)
+      dump_dir = 'dump_out'
+      if '--dump_out_directory' in args:
+        dump_dir = 'other dir/multiple'
+      elif '--dump_out_directory=foo_bar' in args:
+        dump_dir = 'foo_bar'
+      self.assertExists(self.in_dir(f'{dump_dir}/test.dat'))
+      self.assertExists(self.in_dir(f'{dump_dir}/heap.dat'))
+      self.assertExists(self.in_dir(f'{dump_dir}/nested/with space.dat'))
+      stdout = read_file(self.in_dir('stdout.txt'))
+      stderr = read_file(self.in_dir('stderr.txt'))
+      self.assertContained('argc: 6', stdout)
+      self.assertContained('argv[3]: --3', stdout)
+      self.assertContained('argv[4]: escaped space', stdout)
+      self.assertContained('argv[5]: with_underscore', stdout)
+      self.assertContained('Hello, world!', stdout)
+      self.assertContained('Testing ASCII characters: !"$%&\'()*+,-./:;<=>?@[\\]^_`{|}~', stdout)
+      self.assertContained('Testing char sequences: %20%21 &auml;', stdout)
+      self.assertContained('hello, error stream!', stderr)