Automatically report exit status in browser tests

This means that tests don't necessarily need to call REPORT_RESULT.

I'm going to be taking advantage of this in #12923.

Also, don't initialize EXIT_STATUS to zero, but leave it as undefined.
It seems useful to be able to tell the diference between a program that
exits with a zero status and one that has not in fact exited yet.

Author: sbc100

tests/browser_reporting.js

@@ -1,3 +1,5 @@
+var hasModule = typeof Module === 'object' && Module;
+
 /** @param {boolean=} sync
     @param {number=} port */
 function reportResultToServer(result, sync, port) {
@@ -7,9 +9,7 @@ function reportResultToServer(result, sync, port) {
     reportErrorToServer("excessive reported results, sending " + result + ", test will fail");
   }
   reportResultToServer.reported = true;
-
   var xhr = new XMLHttpRequest();
-  var hasModule = typeof Module === 'object' && Module;
   if (hasModule && Module['pageThrewException']) result = 12345;
   xhr.open('GET', 'http://localhost:' + port + '/report_result?' + result, !sync);
   xhr.send();
@@ -36,3 +36,9 @@ if (typeof window === 'object' && window) {
     xhr.send();
   });
 }
+
+if (hasModule) {
+  Module['onExit'] = function(status) {
+    maybeReportResultToServer('exit:' + status);
+  }
+}

tests/report_result.h

@@ -10,17 +10,15 @@
 #ifndef REPORT_RESULT_H_
 #define REPORT_RESULT_H_
 
-#include <stdio.h>
-
 #ifdef __EMSCRIPTEN__
 
-#include <emscripten.h>
-
 #ifdef __cplusplus
 extern "C" {
 #endif
+
 void _ReportResult(int result, int sync);
 void _MaybeReportResult(int result, int sync);
+
 #ifdef __cplusplus
 }
 #endif
@@ -40,7 +38,9 @@ void _MaybeReportResult(int result, int sync);
 
 #else
 
+#include <stdio.h>
 #include <stdlib.h>
+
 #define REPORT_RESULT(result)       \
   do {                              \
     printf("result: %d\n", result); \

tests/test_browser.py

@@ -4548,15 +4548,14 @@ def test_base64_atob_fallback(self):
       #include <stdio.h>
       #include <emscripten.h>
       int main() {
-        REPORT_RESULT(0);
         return 0;
       }
     '''
     create_test_file('test.c', self.with_report_result(src))
     # generate a dummy file
     create_test_file('dummy_file', 'dummy')
     # compile the code with the modularize feature and the preload-file option enabled
-    self.compile_btest(['test.c', '-s', 'MODULARIZE=1', '-s', 'EXPORT_NAME="Foo"', '--preload-file', 'dummy_file', '-s', 'SINGLE_FILE=1'])
+    self.compile_btest(['test.c', '-s', 'EXIT_RUNTIME', '-s', 'MODULARIZE=1', '-s', 'EXPORT_NAME="Foo"', '--preload-file', 'dummy_file', '-s', 'SINGLE_FILE=1'])
     create_test_file('a.html', '''
       <script>
         atob = undefined;
@@ -4567,7 +4566,7 @@ def test_base64_atob_fallback(self):
         var foo = Foo();
       </script>
     ''')
-    self.run_browser('a.html', '...', '/report_result?0')
+    self.run_browser('a.html', '...', '/report_result?exit:0')
 
   # Tests that SINGLE_FILE works as intended in generated HTML (with and without Worker)
   def test_single_file_html(self):