1 files changed, 15 insertions, 7 deletions
diff --git a/tests/test_other.py b/tests/test_other.py
index e381e1b3..2fecf09e 100644
--- a/tests/test_other.py
+++ b/tests/test_other.py
@@ -2521,16 +2521,24 @@ int main()
 }
 ''')
 
+    IMPLICIT_WARNING = '''warning: implicit declaration of function 'strnlen' is invalid in C99'''
+    IMPLICIT_ERROR = '''error: implicit declaration of function 'strnlen' is invalid in C99'''
+
     for opts, expected, compile_expected in [
-      ([], ['abort()', 'it is worth building your source files with -Werror (warnings are errors), as warnings can indicate undefined behavior which can cause this'], []),
-      (['-s', 'ASSERTIONS=2'], ['abort()', 'This pointer might make sense in another type signature'], []),
-      (['-O1'], ['hello 2\nhello 5\n'], []), # invalid output - second arg is sent as varargs, but needs to be int. llvm optimizer avoided the crash silently, caused undefined behavior... at least people can debug this by running an -O0 build.
+      ([], None, [IMPLICIT_ERROR]),
+      (['-Wno-error=implicit-function-declaration'], ['abort()', 'it is worth building your source files with -Werror (warnings are errors), as warnings can indicate undefined behavior which can cause this'], [IMPLICIT_WARNING]), # turn error into warning
+      (['-Wno-implicit-function-declaration'], ['abort()', 'it is worth building your source files with -Werror (warnings are errors), as warnings can indicate undefined behavior which can cause this'], []), # turn error into nothing at all
+      (['-Wno-error=implicit-function-declaration', '-s', 'ASSERTIONS=2'], ['abort()', 'This pointer might make sense in another type signature'], []),
+      (['-Wno-error=implicit-function-declaration', '-O1'], ['hello 2\nhello 5\n'], []), # invalid output - second arg is sent as varargs, but needs to be int. llvm optimizer avoided the crash silently, caused undefined behavior... at least people can debug this by running an -O0 build.
     ]:
       print opts, expected
       stdout, stderr = Popen([PYTHON, EMCC, 'src.c'] + opts, stderr=PIPE).communicate()
-      output = run_js(os.path.join(self.get_dir(), 'a.out.js'), stderr=PIPE, full_output=True)
-      for e in expected:
-        self.assertContained(e, output)
-      for ce in compile_expected + ['''warning: implicit declaration of function 'strnlen' is invalid in C99''', '''warning: incompatible pointer types''']:
+      for ce in compile_expected + ['''warning: incompatible pointer types''']:
         self.assertContained(ce, stderr)
+      if expected is None:
+        assert not os.path.exists('a.out.js')
+      else:
+        output = run_js(os.path.join(self.get_dir(), 'a.out.js'), stderr=PIPE, full_output=True)
+        for e in expected:
+          self.assertContained(e, output)