1 files changed, 48 insertions, 0 deletions
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_css.js b/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_css.js
new file mode 100644
index 0000000000..a75c397b8c
--- /dev/null
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_css.js
@@ -0,0 +1,48 @@
+"use strict";
+
+const server = createHttpServer({ hosts: ["example.com"] });
+
+server.registerPathHandler("/dummy", (request, response) => {
+  response.setStatusLine(request.httpVersion, 200, "OK");
+  response.setHeader("Content-Type", "text/html", false);
+  response.write("<!DOCTYPE html><html></html>");
+});
+
+add_task(async function test_content_script_css() {
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      content_scripts: [
+        {
+          matches: ["http://example.com/dummy"],
+          css: ["content.css"],
+          run_at: "document_start",
+        },
+      ],
+    },
+
+    files: {
+      "content.css": "body { max-width: 42px; }",
+    },
+  });
+
+  await extension.startup();
+
+  let contentPage = await ExtensionTestUtils.loadContentPage(
+    "http://example.com/dummy"
+  );
+
+  function task() {
+    let style = this.content.getComputedStyle(this.content.document.body);
+    return style.maxWidth;
+  }
+
+  let maxWidth = await contentPage.spawn([], task);
+  equal(maxWidth, "42px", "Stylesheet correctly applied");
+
+  await extension.unload();
+
+  maxWidth = await contentPage.spawn([], task);
+  equal(maxWidth, "none", "Stylesheet correctly removed");
+
+  await contentPage.close();
+});