[test] Allow enabling stdio logging using EMTEST_CAPTURE_STDIO. NFC (#24204)

Author: sbc100

test/browser/test_small_js_flags.js.size

@@ -1 +1 @@
-3936
+4241

test/browser_reporting.js

@@ -1,5 +1,5 @@
 // Set this to true to have stdout and stderr sent back to the server
-var captureStdoutStderr = false;
+var captureStdio = false;
 
 var hasModule = typeof Module === 'object' && Module;
 
@@ -76,6 +76,12 @@ function reportTopLevelError(e) {
 }
 
 if (typeof window === 'object' && window) {
+  const urlString = window.location.search;
+  const searchParams = new URLSearchParams(urlString);
+  if (searchParams.has('capture_stdio')) {
+    captureStdio = true;
+  }
+
   window.addEventListener('error', event => {
     reportTopLevelError(event.error || event)
   });
@@ -105,7 +111,8 @@ if (hasModule) {
     Module['onAbort'].proxy = true;
   }
 
-  if (captureStdoutStderr) {
+  if (captureStdio) {
+    console.log("enabling remote stdio logging");
     const origPrint = Module['print'];
     const origPrintErr = Module['printErr'];
 

test/common.py

@@ -71,6 +71,7 @@
 # 2: Log stdout and stderr configure/make. Print out subprocess commands that were executed.
 # 3: Log stdout and stderr, and pass VERBOSE=1 to CMake/configure/make steps.
 EMTEST_BUILD_VERBOSE = int(os.getenv('EMTEST_BUILD_VERBOSE', '0'))
+EMTEST_CAPTURE_STDIO = int(os.getenv('EMTEST_CAPTURE_STDIO', '0'))
 if 'EM_BUILD_VERBOSE' in os.environ:
   exit_with_error('EM_BUILD_VERBOSE has been renamed to EMTEST_BUILD_VERBOSE')
 
@@ -2247,6 +2248,7 @@ class BrowserCore(RunnerCore):
   unresponsive_tests = 0
 
   def __init__(self, *args, **kwargs):
+    self.capture_stdio = EMTEST_CAPTURE_STDIO
     super().__init__(*args, **kwargs)
 
   @classmethod
@@ -2405,7 +2407,8 @@ def btest_exit(self, filename, assert_returncode=0, *args, **kwargs):
 
   def btest(self, filename, expected=None,
             post_build=None,
-            emcc_args=None, url_suffix='', timeout=None,
+            emcc_args=None,
+            timeout=None,
             extra_tries=1,
             reporting=Reporting.FULL,
             output_basename='test'):
@@ -2430,7 +2433,10 @@ def btest(self, filename, expected=None,
       output = self.run_js('test.js')
       self.assertContained('RESULT: ' + expected[0], output)
     else:
-      self.run_browser(outfile + url_suffix, expected=['/report_result?' + e for e in expected], timeout=timeout, extra_tries=extra_tries)
+      url = outfile
+      if self.capture_stdio:
+        url += "?capture_stdio"
+      self.run_browser(url, expected=['/report_result?' + e for e in expected], timeout=timeout, extra_tries=extra_tries)
 
 
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