assertSame('cat:*', CrawlKeywordParser::buildArxivSearchQuery('')); $this->assertSame('cat:*', CrawlKeywordParser::buildArxivSearchQuery(null)); } public function test_build_arxiv_search_query_with_phrase(): void { $this->assertSame('(all:machine AND all:learning)', CrawlKeywordParser::buildArxivSearchQuery('machine learning')); } }