diff --git a/.circleci/config.yml b/.circleci/config.yml
index 6c741f2e32d62..04bbebde4c6f6 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -591,6 +591,7 @@ jobs:
             other.test_node_emscripten_num_logical_cores
             core2.test_pthread_create
             core2.test_i64_invoke_bigint
+            core2.test_sse2
             core2.test_source_map
             core2.test_exceptions_wasm
             core2.test_pthread_unhandledrejection"
@@ -630,6 +631,7 @@ jobs:
       EMTEST_SKIP_V8: "1"
       EMTEST_SKIP_EH: "1"
       EMTEST_SKIP_WASM64: "1"
+      EMTEST_SKIP_SIMD: "1"
     steps:
       - checkout
       - run:
@@ -701,6 +703,7 @@ jobs:
       EMTEST_SKIP_V8: "1"
       EMTEST_SKIP_EH: "1"
       EMTEST_SKIP_WASM64: "1"
+      EMTEST_SKIP_SIMD: "1"
       EMCC_SKIP_SANITY_CHECK: "1"
     steps:
       - run:
diff --git a/test/common.py b/test/common.py
index 1f0a43e9d4d98..8eda93c948fd0 100644
--- a/test/common.py
+++ b/test/common.py
@@ -491,6 +491,23 @@ def require_wasm64(self):
     else:
       self.fail('either d8 or node >= 16 required to run wasm64 tests.  Use EMTEST_SKIP_WASM64 to skip')
 
+  def require_simd(self):
+    if config.NODE_JS and config.NODE_JS in self.js_engines:
+      version = shared.check_node_version()
+      if version >= (16, 0, 0):
+        self.js_engines = [config.NODE_JS]
+        return
+
+    if config.V8_ENGINE and config.V8_ENGINE in self.js_engines:
+      self.emcc_args.append('-sENVIRONMENT=shell')
+      self.js_engines = [config.V8_ENGINE]
+      return
+
+    if 'EMTEST_SKIP_SIMD' in os.environ:
+      self.skipTest('test requires node >= 16 or d8 (and EMTEST_SKIP_SIMD is set)')
+    else:
+      self.fail('either d8 or node >= 16 required to run wasm64 tests.  Use EMTEST_SKIP_SIMD to skip')
+
   def require_wasm_eh(self):
     if config.NODE_JS and config.NODE_JS in self.js_engines:
       version = shared.check_node_version()
diff --git a/test/test_core.py b/test/test_core.py
index 76a6f82d38f3c..afbd0cdbda481 100644
--- a/test/test_core.py
+++ b/test/test_core.py
@@ -39,7 +39,7 @@
 def wasm_simd(f):
   @wraps(f)
   def decorated(self, *args, **kwargs):
-    self.require_v8()
+    self.require_simd()
     if self.get_setting('MEMORY64') == 2:
       self.skipTest('https://github.com/WebAssembly/binaryen/issues/4638')
     if not self.is_wasm():
diff --git a/tools/shared.py b/tools/shared.py
index 79ae2928b32de..b1780587347de 100644
--- a/tools/shared.py
+++ b/tools/shared.py
@@ -94,6 +94,8 @@ def shlex_quote(arg):
 # Switch to shlex.join once we can depend on python 3.8:
 # https://docs.python.org/3/library/shlex.html#shlex.join
 def shlex_join(cmd):
+  if type(cmd) is str:
+    return cmd
   return ' '.join(shlex_quote(x) for x in cmd)