1 files changed, 102 insertions, 0 deletions
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_json_api.js b/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_json_api.js
new file mode 100644
index 0000000000..ca37e2e951
--- /dev/null
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_json_api.js
@@ -0,0 +1,102 @@
+"use strict";
+
+Services.prefs.setBoolPref("extensions.manifestV3.enabled", true);
+
+const server = createHttpServer({ hosts: ["example.com"] });
+server.registerPathHandler("/dummy", (request, response) => {
+  response.setStatusLine(request.httpVersion, 200, "OK");
+  response.write(
+    `<script>
+      // Clobber the JSON API to allow us to confirm that the page's value for
+      // the "JSON" object does not affect the content script's JSON API.
+      window.JSON = new String("overridden by page");
+      window.objFromPage = { serializeMe: "thanks" };
+      window.objWithToJSON = { toJSON: () => "toJSON ran", should_not_see: 1 };
+      </script>
+    `
+  );
+});
+
+async function test_JSON_parse_and_stringify({ manifest_version }) {
+  let extension = ExtensionTestUtils.loadExtension({
+    temporarilyInstalled: true, // Needed for granted_host_permissions
+    manifest: {
+      manifest_version,
+      granted_host_permissions: true, // Test-only: grant permissions in MV3.
+      host_permissions: ["http://example.com/"], // Work-around for bug 1766752.
+      content_scripts: [
+        {
+          matches: ["http://example.com/dummy"],
+          run_at: "document_end",
+          js: ["contentscript.js"],
+        },
+      ],
+    },
+    files: {
+      "contentscript.js"() {
+        let json = `{"a":[123,true,null]}`;
+        browser.test.assertEq(
+          JSON.stringify({ a: [123, true, null] }),
+          json,
+          "JSON.stringify with basic values"
+        );
+        let parsed = JSON.parse(json);
+        browser.test.assertTrue(
+          parsed instanceof Object,
+          "Parsed JSON is an Object"
+        );
+        browser.test.assertTrue(
+          parsed.a instanceof Array,
+          "Parsed JSON has an Array"
+        );
+        browser.test.assertEq(
+          JSON.stringify(parsed),
+          json,
+          "JSON.stringify for parsed JSON returns original input"
+        );
+        browser.test.assertEq(
+          JSON.stringify({ toJSON: () => "overridden", hideme: true }),
+          `"overridden"`,
+          "JSON.parse with toJSON method"
+        );
+
+        browser.test.assertEq(
+          JSON.stringify(window.wrappedJSObject.objFromPage),
+          `{"serializeMe":"thanks"}`,
+          "JSON.parse with value from the page"
+        );
+
+        browser.test.assertEq(
+          JSON.stringify(window.wrappedJSObject.objWithToJSON),
+          `"toJSON ran"`,
+          "JSON.parse with object with toJSON method from the page"
+        );
+
+        browser.test.assertTrue(JSON === globalThis.JSON, "JSON === this.JSON");
+        browser.test.assertTrue(JSON === window.JSON, "JSON === window.JSON");
+        browser.test.assertEq(
+          "overridden by page",
+          window.wrappedJSObject.JSON.toString(),
+          "page's JSON object is still the original value (overridden by page)"
+        );
+        browser.test.sendMessage("done");
+      },
+    },
+  });
+  await extension.startup();
+
+  let contentPage = await ExtensionTestUtils.loadContentPage(
+    "http://example.com/dummy"
+  );
+  await extension.awaitMessage("done");
+  await contentPage.close();
+  await extension.unload();
+}
+
+add_task(async function test_JSON_apis_MV2() {
+  await test_JSON_parse_and_stringify({ manifest_version: 2 });
+});
+
+add_task(async function test_JSON_apis_MV3() {
+  await test_JSON_parse_and_stringify({ manifest_version: 3 });
+});