test(08-01): add failing tests for ZhihuCrawler

- Add test_answer_crawler.py with tests for crawl_answer()
- Add test_article_crawler.py with tests for crawl_article()
- Add test_metadata_extraction.py with tests for author/metadata parsing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_crawler/test_answer_crawler.py

@@ -0,0 +1,93 @@
+"""Tests for Zhihu Answer Crawler"""
+
+import pytest
+from unittest.mock import MagicMock, patch, PropertyMock
+
+from kb_workflow.crawler.models import AnswerData, CrawlResult
+
+
+class TestCrawlAnswer:
+    """Tests for crawl_answer() method."""
+
+    def test_crawl_answer_returns_crawl_result(self, mock_browser, sample_answer_url):
+        """Test that crawl_answer returns a CrawlResult object."""
+        from kb_workflow.crawler.zhihu_crawler import ZhihuCrawler
+
+        with patch.object(ZhihuCrawler, '_get_cookie', return_value='test_cookie'):
+            with patch('kb_workflow.crawler.zhihu_crawler.PlaywrightBrowser') as mock_pb:
+                mock_pb_instance = MagicMock()
+                mock_pb.return_value = mock_pb_instance
+                mock_pb_instance.page = MagicMock()
+                mock_pb_instance.page.route = MagicMock()
+
+                crawler = ZhihuCrawler(headless=True, timeout=10)
+                result = crawler.crawl_answer(sample_answer_url)
+
+                assert isinstance(result, CrawlResult)
+
+    def test_crawl_answer_invalid_url_returns_failure(self):
+        """Test that invalid URL returns CrawlResult with success=False."""
+        from kb_workflow.crawler.zhihu_crawler import ZhihuCrawler
+
+        crawler = ZhihuCrawler(headless=True, timeout=10)
+        result = crawler.crawl_answer("https://www.example.com/invalid")
+
+        assert result.success is False
+        assert result.error is not None
+        assert "Invalid" in result.error
+
+    def test_crawl_answer_extracts_question_title(
+        self, sample_answer_url, sample_answer_api_response
+    ):
+        """Test that crawl_answer extracts question title from API response."""
+        from kb_workflow.crawler.zhihu_crawler import ZhihuCrawler, ZhihuApiInterceptor
+
+        # Create interceptor with captured data
+        interceptor = ZhihuApiInterceptor()
+        interceptor.captured_data["answer"] = sample_answer_api_response
+
+        crawler = ZhihuCrawler(headless=True, timeout=10)
+
+        # Test the parse method directly
+        result_data = crawler._parse_answer_data(
+            sample_answer_api_response,
+            answer_id=123456789,
+            question_id=987654321
+        )
+
+        assert result_data.question_title == "What is the best way to learn programming?"
+
+
+class TestAnswerDataExtraction:
+    """Tests for answer data extraction."""
+
+    def test_parse_answer_data_contains_content(self, sample_answer_api_response):
+        """Test that parsed answer contains content."""
+        from kb_workflow.crawler.zhihu_crawler import ZhihuCrawler
+
+        crawler = ZhihuCrawler(headless=True, timeout=10)
+        result = crawler._parse_answer_data(
+            sample_answer_api_response,
+            answer_id=123456789,
+            question_id=987654321
+        )
+
+        assert isinstance(result, AnswerData)
+        assert result.content == "<p>This is a sample answer content in HTML format.</p>"
+        assert result.excerpt == "This is a sample answer content..."
+
+    def test_parse_answer_data_contains_metadata(self, sample_answer_api_response):
+        """Test that parsed answer contains metadata."""
+        from kb_workflow.crawler.zhihu_crawler import ZhihuCrawler
+
+        crawler = ZhihuCrawler(headless=True, timeout=10)
+        result = crawler._parse_answer_data(
+            sample_answer_api_response,
+            answer_id=123456789,
+            question_id=987654321
+        )
+
+        assert result.metadata.voteup_count == 1000
+        assert result.metadata.comment_count == 50
+        assert result.metadata.author is not None
+        assert result.metadata.author.name == "John Doe"