Add browser test for SOURCE_PHASE_IMPORTS. NFC (#24667)

This feature is now available in chrome 139.0.7251.0.

Author: sbc100

.circleci/config.yml

@@ -317,7 +317,7 @@ commands:
             EMTEST_DETECT_TEMPFILE_LEAKS: "0"
             # --no-sandbox because we are running as root and chrome requires
             # this flag for now: https://crbug.com/638180
-            CHROME_FLAGS_BASE: "--no-first-run -start-maximized --no-sandbox --use-gl=swiftshader --user-data-dir=/tmp/chrome-emscripten-profile --enable-experimental-web-platform-features"
+            CHROME_FLAGS_BASE: "--no-first-run -start-maximized --no-sandbox --use-gl=swiftshader --user-data-dir=/tmp/chrome-emscripten-profile --enable-experimental-web-platform-features --enable-features=JavaScriptSourcePhaseImports"
             # Increase the window size to avoid flaky sdl tests see #24236.
             CHROME_FLAGS_HEADLESS: "--headless=new --window-size=1024,768 --remote-debugging-port=1234"
             CHROME_FLAGS_WASM: "--enable-experimental-webassembly-features --js-flags=\"--experimental-wasm-stack-switching --experimental-wasm-type-reflection\""

test/test_browser.py

@@ -3424,6 +3424,17 @@ def test_modularize(self, args, code, opts):
     ''' % code)
     self.run_browser('a.html', '/report_result?0')
 
+  @no_firefox('source phase imports not implemented yet in firefox')
+  def test_source_phase_imports(self):
+    self.compile_btest('browser_test_hello_world.c', ['-sEXPORT_ES6', '-sSOURCE_PHASE_IMPORTS', '-Wno-experimental', '-o', 'out.mjs'])
+    create_file('a.html', '''
+      <script type="module">
+        import Module from "./out.mjs"
+        const mod = await Module();
+      </script>
+    ''')
+    self.run_browser('a.html', '/report_result?0')
+
   def test_modularize_network_error(self):
     self.compile_btest('browser_test_hello_world.c', ['-sMODULARIZE', '-sEXPORT_NAME=createModule'], reporting=Reporting.NONE)
     shutil.copy(test_file('browser_reporting.js'), '.')