[digitalocean|compute] added list_ssh_keys request tests

tests/digitalocean/requests/compute/list_ssh_keys_tests.rb

@@ -0,0 +1,21 @@
+Shindo.tests('Fog::Compute[:digitalocean] | list_ssh_keys request', ['digitalocean', 'compute']) do
+
+  @ssh_key_format = {
+    'id'           => Integer,
+    'name'         => String
+  }
+
+  tests('success') do
+
+    tests('#list_ssh_keys') do
+      Fog::Compute[:digitalocean].create_ssh_key 'fookey', 'ssh-dss FOO'
+      Fog::Compute[:digitalocean].list_ssh_keys.body['ssh_keys'].each do |key|
+        tests('format').data_matches_schema(@ssh_key_format) do
+          key
+        end
+      end
+    end
+
+  end
+
+end