Always render a <button disabled> when rendering disabled Buttons

src/components/Button/Button.tsx

@@ -157,7 +157,8 @@ function Button({
 
   const type = submit ? 'submit' : 'button';
 
-  return url ? (
+  // UnstyledLinks cant be disabled so always render a button when disabled
+  return url && !isDisabled ? (
     <UnstyledLink
       id={id}
       url={url}

src/components/Button/tests/Button.test.tsx

@@ -60,30 +60,30 @@ describe('<Button />', () => {
   });
 
   describe('disabled', () => {
-    it('disables the <button> by adding the disabled attribute', () => {
+    it('disable without a url renders <button disabled>', () => {
       const button = shallowWithAppProvider(<Button disabled />);
       expect(button.find('button').prop('disabled')).toBeTruthy();
     });
 
-    it('does not add the disabled attribute to the <a> as `<a disabled>` is invalid HTML', () => {
+    it('disable with a url renders <button disabled> (as <a disabled> is invalid HTML)>', () => {
       const button = shallowWithAppProvider(
         <Button disabled url="http://google.com" />,
       );
-      expect(button.find(UnstyledLink).prop('disabled')).toBeFalsy();
+      expect(button.find('button').prop('disabled')).toBeTruthy();
     });
   });
 
   describe('loading', () => {
-    it('disables the <button> by adding the disabled attribute', () => {
+    it('loading without a url renders <button disabled>', () => {
       const button = shallowWithAppProvider(<Button loading />);
       expect(button.find('button').prop('disabled')).toBe(true);
     });
 
-    it('does not add the disabled attribute to the <a> as `<a disabled>` is invalid HTML', () => {
+    it('loading with a url renders <button disabled> (as <a disabled> is invalid HTML)', () => {
       const button = shallowWithAppProvider(
         <Button loading url="http://google.com" />,
       );
-      expect(button.find(UnstyledLink).prop('disabled')).toBeFalsy();
+      expect(button.find('button').prop('disabled')).toBeTruthy();
     });
 
     it('renders a spinner into the button', () => {