test(12-01): add failing tests for SRT parser module

- Test standard SRT format parsing
- Test special character handling
- Test error handling for invalid/empty content
- Test file parsing functionality

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

tests/test_srt_processor.py

@@ -0,0 +1,151 @@
+"""Tests for SRT processing module
+
+Tests for:
+- SRT parser (parse_srt, parse_srt_file)
+- Semantic segmenter (SemanticSegmenter)
+- ASR corrector (ASRCorrector)
+- SRTProcessor (pipeline processor)
+"""
+
+import pytest
+from pathlib import Path
+from dataclasses import dataclass
+from typing import List, Optional
+
+
+# =============================================================================
+# Test Fixtures
+# =============================================================================
+
+@pytest.fixture
+def sample_srt_content() -> str:
+    """标准 SRT 格式内容"""
+    return """1
+00:00:00,000 --> 00:00:05,000
+第一句字幕内容
+
+2
+00:00:05,000 --> 00:00:10,000
+第二句字幕内容
+
+3
+00:00:10,000 --> 00:00:15,000
+第三句字幕内容
+"""
+
+
+@pytest.fixture
+def sample_srt_with_special_chars() -> str:
+    """包含特殊字符的 SRT 内容"""
+    return """1
+00:00:00,000 --> 00:00:05,000
+你好，世界！这是测试。
+
+2
+00:00:05,000 --> 00:00:10,000
+包含特殊字符：<>&"'
+
+3
+00:00:10,000 --> 00:00:15,000
+多行
+字幕内容
+"""
+
+
+@pytest.fixture
+def invalid_srt_content() -> str:
+    """格式错误的 SRT 内容"""
+    return "这不是有效的 SRT 格式"
+
+
+@pytest.fixture
+def empty_content() -> str:
+    """空内容"""
+    return ""
+
+
+@pytest.fixture
+def sample_srt_file(tmp_path: Path, sample_srt_content: str) -> Path:
+    """创建临时 SRT 文件"""
+    srt_file = tmp_path / "test.srt"
+    srt_file.write_text(sample_srt_content, encoding="utf-8")
+    return srt_file
+
+
+# =============================================================================
+# Test 1: SRT Parser - parse_srt
+# =============================================================================
+
+class TestParseSrt:
+    """测试 SRT 解析功能"""
+
+    def test_parse_standard_srt(self, sample_srt_content: str):
+        """Test 1: 标准的 SRT 格式能被正确解析为 Segment 列表"""
+        from kb_workflow.srt.parser import parse_srt, Segment
+
+        segments = parse_srt(sample_srt_content)
+
+        assert len(segments) == 3
+        assert all(isinstance(s, Segment) for s in segments)
+
+        # 验证第一个 segment
+        assert segments[0].id == 1
+        assert segments[0].start_time == 0.0
+        assert segments[0].end_time == 5.0
+        assert segments[0].text == "第一句字幕内容"
+
+        # 验证最后一个 segment
+        assert segments[2].id == 3
+        assert segments[2].start_time == 10.0
+        assert segments[2].end_time == 15.0
+        assert segments[2].text == "第三句字幕内容"
+
+    def test_parse_srt_with_special_chars(self, sample_srt_with_special_chars: str):
+        """Test 2: 包含特殊字符的字幕能正确处理"""
+        from kb_workflow.srt.parser import parse_srt
+
+        segments = parse_srt(sample_srt_with_special_chars)
+
+        assert len(segments) == 3
+        assert "你好，世界！" in segments[0].text
+        assert "<>&\"'" in segments[1].text
+        # 多行字幕应该合并
+        assert "多行" in segments[2].text
+
+    def test_parse_invalid_srt_raises_error(self, invalid_srt_content: str):
+        """Test 3: 空文件或格式错误的文件抛出 ValueError"""
+        from kb_workflow.srt.parser import parse_srt
+
+        with pytest.raises(ValueError, match="Invalid SRT format"):
+            parse_srt(invalid_srt_content)
+
+    def test_parse_empty_content_raises_error(self, empty_content: str):
+        """Test 3b: 空内容抛出 ValueError"""
+        from kb_workflow.srt.parser import parse_srt
+
+        with pytest.raises(ValueError, match="Empty SRT content"):
+            parse_srt(empty_content)
+
+
+# =============================================================================
+# Test 1b: SRT Parser - parse_srt_file
+# =============================================================================
+
+class TestParseSrtFile:
+    """测试从文件解析 SRT"""
+
+    def test_parse_srt_file(self, sample_srt_file: Path):
+        """从文件解析 SRT"""
+        from kb_workflow.srt.parser import parse_srt_file
+
+        segments = parse_srt_file(sample_srt_file)
+
+        assert len(segments) == 3
+        assert segments[0].text == "第一句字幕内容"
+
+    def test_parse_nonexistent_file_raises_error(self):
+        """不存在的文件抛出 FileNotFoundError"""
+        from kb_workflow.srt.parser import parse_srt_file
+
+        with pytest.raises(FileNotFoundError):
+            parse_srt_file(Path("/nonexistent/file.srt"))