diff --git a/appvalidator/testcases/webappbase.py b/appvalidator/testcases/webappbase.py
index 3f4bced..7b16014 100644
--- a/appvalidator/testcases/webappbase.py
+++ b/appvalidator/testcases/webappbase.py
@@ -101,7 +101,11 @@ def try_get_resource(err, package, url, filename, resource_type="URL",
                 filename=filename)
             return
 
-        request.raw.close()
+        try:
+            request.raw.close()
+        except AttributeError:
+            # Some versions of requests don't support close().
+            pass
 
         if not data:
             generic_http_error()
@@ -142,6 +146,12 @@ def try_get_resource(err, package, url, filename, resource_type="URL",
 
 
 def test_icon(err, data, url, size):
+    try:
+        size = int(size)
+    except ValueError:
+        # This is handled elsewhere.
+        return
+
     try:
         icon = Image.open(data)
         icon.verify()
@@ -193,6 +203,13 @@ def test_app_resources(err, package):
     icon_urls = set()
     icons = manifest.get("icons", {}).items()
     for icon_size, url in icons:
+
+        try:
+            icon_size = int(icon_size)
+        except ValueError:
+            # There will be an error for this someplace else.
+            continue
+
         # Don't test the same icon URL twice.
         if url in icon_urls:
             continue
diff --git a/tests/test_webapp_resources.py b/tests/test_webapp_resources.py
index 14e143c..274c3e5 100644
--- a/tests/test_webapp_resources.py
+++ b/tests/test_webapp_resources.py
@@ -273,6 +273,9 @@ class TestIconProperties(TestCase):
         self._test_icon("icon-128.png", 128)
         self.assert_silent()
 
+        self._test_icon("icon-128.png", "128")
+        self.assert_silent()
+
     def test_bad_icon(self):
         self._test_icon("corrupt.xpi", 128)
         self.assert_failed(with_errors=True)
@@ -281,6 +284,10 @@ class TestIconProperties(TestCase):
         self._test_icon("icon-128x64.png", 128)
         self.assert_failed(with_errors=True)
 
+        self.setup_err()
+        self._test_icon("icon-128x64.png", "128")
+        self.assert_failed(with_errors=True)
+
     def test_bad_size(self):
         self._test_icon("icon-128.png", 256)
         self.assert_failed(with_errors=True)