Fix issues in tests

add headers Server and Date
check queries for empty string and not int

frameworks/Crystal/kemal/server-postgres.cr

@@ -38,6 +38,7 @@ end
 
 private def sanitizedQueryCount(request)
   queries = request.params["queries"] as String
+  return 1 if queries.empty? || queries.to_i?.nil?
   if queries.to_i > 500
     queries = 500
   elsif queries.to_i < 1
@@ -46,6 +47,11 @@ private def sanitizedQueryCount(request)
   queries.to_i
 end
 
+before_all do |env|
+  env.response.headers["Server"] = "Kemal"
+  env.response.headers["Date"] = Time.now.to_s
+end
+
 #
 # Basic Tests
 #