[enh] add checker

searx/search/processors/online_currency.py

@@ -55,3 +55,13 @@ class OnlineCurrencyProcessor(OnlineProcessor):
         params['from_name'] = iso4217_to_name(from_currency, 'en')
         params['to_name'] = iso4217_to_name(to_currency, 'en')
         return params
+
+    def get_default_tests(self):
+        tests = {}
+
+        tests['currency'] = {
+            'matrix': {'query': '1337 usd in rmb'},
+            'result_container': ['has_answer'],
+        }
+
+        return tests