test(07-02): add failing tests for Cookie JSON parsing

- Test parse_json_cookies for Chrome Cookie Editor format
- Test domain filtering for zhihu.com
- Test empty array handling
- Test malformed JSON error handling
- Test file not found error handling

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

kb_workflow/auth/__init__.py

@@ -0,0 +1,4 @@
+"""Auth module for KB Workflow
+
+Provides authentication and cookie management functionality.
+"""

tests/test_auth/__init__.py

@@ -0,0 +1 @@
+"""Tests for auth module"""

tests/test_auth/test_cookie_import.py

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+"""Tests for Cookie JSON parsing functionality
+
+Tests parse_json_cookies function for Chrome Cookie Editor JSON format.
+"""
+
+import json
+import pytest
+from pathlib import Path
+
+from kb_workflow.auth.cookie_manager import parse_json_cookies
+
+
+class TestParseJsonCookies:
+    """Test suite for parse_json_cookies function"""
+
+    def test_parse_json_cookies(self, tmp_path: Path):
+        """Test parsing Chrome Cookie Editor JSON format"""
+        # Arrange: Create a valid JSON file with Chrome Cookie Editor format
+        cookie_data = [
+            {"name": "z_c0", "value": "token123", "domain": ".zhihu.com"},
+            {"name": "_zap", "value": "zap_value", "domain": ".zhihu.com"},
+        ]
+        json_file = tmp_path / "cookies.json"
+        json_file.write_text(json.dumps(cookie_data), encoding="utf-8")
+
+        # Act
+        result = parse_json_cookies(str(json_file))
+
+        # Assert
+        assert result == "z_c0=token123; _zap=zap_value"
+
+    def test_parse_json_cookies_filters_domain(self, tmp_path: Path):
+        """Test that only zhihu.com domain cookies are kept"""
+        # Arrange: Mix of domains
+        cookie_data = [
+            {"name": "z_c0", "value": "zhihu_token", "domain": ".zhihu.com"},
+            {"name": "other_cookie", "value": "other_value", "domain": ".other.com"},
+            {"name": "_zap", "value": "zap_value", "domain": "zhihu.com"},
+        ]
+        json_file = tmp_path / "cookies.json"
+        json_file.write_text(json.dumps(cookie_data), encoding="utf-8")
+
+        # Act
+        result = parse_json_cookies(str(json_file))
+
+        # Assert: Only zhihu.com cookies included
+        assert "z_c0=zhihu_token" in result
+        assert "_zap=zap_value" in result
+        assert "other_cookie" not in result
+
+    def test_parse_json_cookies_empty(self, tmp_path: Path):
+        """Test that empty array returns empty string"""
+        # Arrange
+        json_file = tmp_path / "cookies.json"
+        json_file.write_text("[]", encoding="utf-8")
+
+        # Act
+        result = parse_json_cookies(str(json_file))
+
+        # Assert
+        assert result == ""
+
+    def test_parse_json_cookies_malformed(self, tmp_path: Path):
+        """Test that malformed JSON raises ValueError"""
+        # Arrange: Invalid JSON content
+        json_file = tmp_path / "cookies.json"
+        json_file.write_text("{not valid json}", encoding="utf-8")
+
+        # Act & Assert
+        with pytest.raises(ValueError, match="Invalid JSON format"):
+            parse_json_cookies(str(json_file))
+
+    def test_parse_json_cookies_file_not_found(self):
+        """Test that non-existent file raises ValueError"""
+        # Act & Assert
+        with pytest.raises(ValueError, match="Cookie file not found"):
+            parse_json_cookies("/non/existent/path/cookies.json")
+
+    def test_parse_json_cookies_not_array(self, tmp_path: Path):
+        """Test that non-array JSON raises ValueError"""
+        # Arrange: JSON object instead of array
+        json_file = tmp_path / "cookies.json"
+        json_file.write_text('{"name": "test"}', encoding="utf-8")
+
+        # Act & Assert
+        with pytest.raises(ValueError, match="Expected JSON array"):
+            parse_json_cookies(str(json_file))