content/shell/browser/rust_mojo_test_browsertest.cc

// Copyright 2026 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/path_service.h"
#include "base/test/scoped_feature_list.h"
#include "build/build_config.h"
#include "content/public/common/content_switches.h"
#include "content/public/test/browser_test.h"
#include "content/public/test/browser_test_utils.h"
#include "content/public/test/content_browser_test.h"
#include "content/public/test/content_browser_test_utils.h"
#include "content/shell/browser/shell.h"

namespace content {

class RustMojoTestBrowserTest : public ContentBrowserTest {
 public:
  void SetUpCommandLine(base::CommandLine* command_line) override {
    command_line->AppendSwitchASCII(switches::kEnableBlinkFeatures,
                                    "MojoJS,MojoJSTest");
  }

  void SetUpOnMainThread() override {
    ContentBrowserTest::SetUpOnMainThread();
    base::FilePath out_dir;
    base::PathService::Get(base::DIR_OUT_TEST_DATA_ROOT, &out_dir);
    // Serve the build directory so that /gen/ paths resolve correctly.
    embedded_test_server()->ServeFilesFromDirectory(out_dir);
    embedded_test_server()->ServeFilesFromDirectory(
        GetTestFilePath(nullptr, ""));
    ASSERT_TRUE(embedded_test_server()->Start());
  }
};

class RustMojoTestBrowserTestWithFeatureEnabled
    : public RustMojoTestBrowserTest {
 public:
  RustMojoTestBrowserTestWithFeatureEnabled() {
    // Presently, Rust's `base_feature!` macro doesn't default to exporting
    // Features declared on the Rust side, and thus the C++ side doesn't have
    // a direct way to reference them. crrev/7802270 will fix this by having
    // that macro export symbols by default, but in the meantime, we use
    // InitFromCommandLine here so we can successfully test the feature.
    feature_list_.InitFromCommandLine("FeatureFlagSetViaRust", "");
  }

 private:
  base::test::ScopedFeatureList feature_list_;
};

// TODO(crbug.com/444509367): Failing on Fushia.
#if BUILDFLAG(IS_FUCHSIA)
#define MAYBE_LoadRustMojoService DISABLED_LoadRustMojoService
#define MAYBE_LoadRustMojoServiceWithFeatureEnabled \
  DISABLED_LoadRustMojoServiceWithFeatureEnabled
#else
#define MAYBE_LoadRustMojoService LoadRustMojoService
#define MAYBE_LoadRustMojoServiceWithFeatureEnabled \
  LoadRustMojoServiceWithFeatureEnabled
#endif
IN_PROC_BROWSER_TEST_F(RustMojoTestBrowserTest, MAYBE_LoadRustMojoService) {
  EXPECT_TRUE(NavigateToURL(
      shell(), embedded_test_server()->GetURL("/rust_mojo_test.html")));
  EXPECT_EQ("Rust says hi.", EvalJs(shell(), "getRustMessage(1)"));

  // Verify that the feature flag is disabled by default.
  EXPECT_EQ(false,
            EvalJs(shell(),
                   "content.rustTest.mojom.RustTestService.getRemote()."
                   "isFeatureFlagSetViaRustEnabled().then(r => r.enabled)"));
}

IN_PROC_BROWSER_TEST_F(RustMojoTestBrowserTestWithFeatureEnabled,
                       MAYBE_LoadRustMojoServiceWithFeatureEnabled) {
  EXPECT_TRUE(NavigateToURL(
      shell(), embedded_test_server()->GetURL("/rust_mojo_test.html")));

  // Verify that the feature flag is enabled.
  EXPECT_EQ(true,
            EvalJs(shell(),
                   "content.rustTest.mojom.RustTestService.getRemote()."
                   "isFeatureFlagSetViaRustEnabled().then(r => r.enabled)"));
}

}  // namespace content