diff --git a/common/extensions/BUILD.bazel b/common/extensions/BUILD.bazel
index 72105685e0091..f3c42851d3646 100644
--- a/common/extensions/BUILD.bazel
+++ b/common/extensions/BUILD.bazel
@@ -17,6 +17,8 @@ filegroup(
 exports_files(
     [
         "webextensions-selenium-example.xpi",
+        "webextensions-selenium-example.zip",
+        "webextensions-selenium-example-unsigned.zip",
     ],
     visibility = [
         "//java/test/org/openqa/selenium/firefox:__pkg__",
diff --git a/py/BUILD.bazel b/py/BUILD.bazel
index 7f6ca945e3eaf..7a94b08f00b66 100644
--- a/py/BUILD.bazel
+++ b/py/BUILD.bazel
@@ -76,9 +76,21 @@ copy_file(
 )
 
 copy_file(
-    name = "favourite_color",
+    name = "webextensions-selenium-example-xpi",
     src = "//common/extensions:webextensions-selenium-example.xpi",
-    out = "test/selenium/webdriver/firefox/webextensions-selenium-example.xpi",
+    out = "test/extensions/webextensions-selenium-example.xpi",
+)
+
+copy_file(
+    name = "webextensions-selenium-example-zip",
+    src = "//common/extensions:webextensions-selenium-example.zip",
+    out = "test/extensions/webextensions-selenium-example.zip",
+)
+
+copy_file(
+    name = "webextensions-selenium-example-unsigned-zip",
+    src = "//common/extensions:webextensions-selenium-example-unsigned.zip",
+    out = "test/extensions/webextensions-selenium-example-unsigned.zip",
 )
 
 py_library(
@@ -207,8 +219,9 @@ py_library(
         "setup.cfg",
         "test/selenium/webdriver/common/test_file.txt",
         "test/selenium/webdriver/common/test_file2.txt",
-        ":favourite_color",
-
+        ":webextensions-selenium-example-xpi",
+        ":webextensions-selenium-example-zip",
+        ":webextensions-selenium-example-unsigned-zip",
     ],
     imports = ["."],
     deps = [
@@ -376,9 +389,6 @@ py_test_suite(
         "--instafail",
         "--driver=firefox",
     ],
-    data = [
-        "//common/extensions",
-    ],
     tags = [
         "no-sandbox",
     ],
@@ -401,7 +411,6 @@ py_test_suite(
         "--driver=remote",
     ],
     data = [
-        "//common/extensions",
         "//java/src/org/openqa/selenium/grid:selenium_server_deploy.jar",
     ],
     tags = [
diff --git a/py/test/selenium/webdriver/firefox/ff_installs_addons_tests.py b/py/test/selenium/webdriver/firefox/ff_installs_addons_tests.py
index 3dc82e746468e..b13ed994e6ba1 100644
--- a/py/test/selenium/webdriver/firefox/ff_installs_addons_tests.py
+++ b/py/test/selenium/webdriver/firefox/ff_installs_addons_tests.py
@@ -16,32 +16,90 @@
 # under the License.
 
 import os
+import zipfile
 
-from selenium.common.exceptions import WebDriverException
+from selenium.webdriver.common.by import By
 
+extensions = os.path.abspath("../../../../../../test/extensions/")
 
-def test_install_addon_temporary(driver):
-    extension = os.path.join(os.path.dirname(os.path.abspath(__file__)),
-                             'webextensions-selenium-example.xpi')
 
-    id = driver.install_addon(extension, True)
+def test_install_uninstall_signed_addon_xpi(driver, pages):
+    extension = os.path.join(extensions, "webextensions-selenium-example.xpi")
+
+    id = driver.install_addon(extension)
     assert id == 'webextensions-selenium-example@example.com'
 
+    pages.load("blank.html")
+    injected = driver.find_element(By.ID, "webextensions-selenium-example")
+    assert injected.text == "Content injected by webextensions-selenium-example"
+
+    driver.uninstall_addon(id)
+    driver.refresh()
+    assert len(driver.find_elements(By.ID, "webextensions-selenium-example")) == 0
 
-def test_install_addon(driver):
-    extension = os.path.join(os.path.dirname(os.path.abspath(__file__)),
-                             'webextensions-selenium-example.xpi')
 
-    id = driver.install_addon(extension, False)
+def test_install_uninstall_signed_addon_zip(driver, pages):
+    extension = os.path.join(extensions, "webextensions-selenium-example.zip")
+
+    id = driver.install_addon(extension)
     assert id == 'webextensions-selenium-example@example.com'
 
+    pages.load("blank.html")
+    injected = driver.find_element(By.ID, "webextensions-selenium-example")
+    assert injected.text == "Content injected by webextensions-selenium-example"
 
-def test_uninstall_addon(driver):
-    extension = os.path.join(os.path.dirname(os.path.abspath(__file__)),
-                             'webextensions-selenium-example.xpi')
+    driver.uninstall_addon(id)
+    driver.refresh()
+    assert len(driver.find_elements(By.ID, "webextensions-selenium-example")) == 0
 
-    id = driver.install_addon(extension)
-    try:
-        driver.uninstall_addon(id)
-    except WebDriverException as exc:
-        assert False, exc
+
+def test_install_uninstall_unsigned_addon_zip(driver, pages):
+    extension = os.path.join(extensions, 'webextensions-selenium-example-unsigned.zip')
+
+    id = driver.install_addon(extension, temporary=True)
+    assert id == 'webextensions-selenium-example@example.com'
+
+    pages.load("blank.html")
+    injected = driver.find_element(By.ID, "webextensions-selenium-example")
+    assert injected.text == "Content injected by webextensions-selenium-example"
+
+    driver.uninstall_addon(id)
+    driver.refresh()
+    assert len(driver.find_elements(By.ID, "webextensions-selenium-example")) == 0
+
+
+def test_install_uninstall_signed_addon_dir(driver, pages):
+    zip = os.path.join(extensions, 'webextensions-selenium-example.zip')
+
+    target = os.path.join(extensions, 'webextensions-selenium-example')
+    with zipfile.ZipFile(zip, 'r') as zip_ref:
+        zip_ref.extractall(target)
+
+    id = driver.install_addon(target)
+    assert id == 'webextensions-selenium-example@example.com'
+
+    pages.load("blank.html")
+    injected = driver.find_element(By.ID, "webextensions-selenium-example")
+    assert injected.text == "Content injected by webextensions-selenium-example"
+
+    driver.uninstall_addon(id)
+    driver.refresh()
+    assert len(driver.find_elements(By.ID, "webextensions-selenium-example")) == 0
+
+
+def test_install_uninstall_unsigned_addon_dir(driver, pages):
+    zip = os.path.join(extensions, 'webextensions-selenium-example-unsigned.zip')
+    target = os.path.join(extensions, 'webextensions-selenium-example-unsigned')
+    with zipfile.ZipFile(zip, 'r') as zip_ref:
+        zip_ref.extractall(target)
+
+    id = driver.install_addon(target, temporary=True)
+    assert id == 'webextensions-selenium-example@example.com'
+
+    pages.load("blank.html")
+    injected = driver.find_element(By.ID, "webextensions-selenium-example")
+    assert injected.text == "Content injected by webextensions-selenium-example"
+
+    driver.uninstall_addon(id)
+    driver.refresh()
+    assert len(driver.find_elements(By.ID, "webextensions-selenium-example")) == 0