perf: webapp事件接口加分页、motion默认隔帧采样、新增20个单元测试

- /api/events 支持 limit/offset 分页参数，默认500上限2000
- MOTION_SAMPLE_STRIDE 默认从1改为2，长视频提速一倍
- 新增 tests/test_core.py：覆盖MD5、活动窗口合并、摔倒检测、活动标签合并、Ollama解析等20个纯函数测试

tests/test_core.py

@@ -0,0 +1,135 @@
+"""基础单元测试：覆盖不依赖外部工具/模型的纯函数。
+
+运行：.venv/bin/python -m pytest tests/ -v
+或：.venv/bin/python tests/test_core.py
+"""
+import hashlib
+import os
+import tempfile
+import unittest
+
+from analysis.hashing import compute_md5
+from analysis.motion_filter import merge_motion_windows
+from analysis.fall_detector import _find_fall_windows
+from analysis.activity_tagger import _merge_labeled_samples
+from analysis.ollama_client import _parse_label
+
+
+class TestHashing(unittest.TestCase):
+    def test_compute_md5_matches_hashlib(self):
+        with tempfile.NamedTemporaryFile(delete=False) as f:
+            f.write(b"hello world" * 1000)
+            path = f.name
+        try:
+            expected = hashlib.md5(b"hello world" * 1000).hexdigest()
+            self.assertEqual(compute_md5(path), expected)
+        finally:
+            os.unlink(path)
+
+    def test_compute_md5_empty_file(self):
+        with tempfile.NamedTemporaryFile(delete=False) as f:
+            path = f.name
+        try:
+            self.assertEqual(compute_md5(path), hashlib.md5(b"").hexdigest())
+        finally:
+            os.unlink(path)
+
+
+class TestMergeMotionWindows(unittest.TestCase):
+    def test_single_window(self):
+        flags = [(0.0, True), (0.5, True), (1.0, True)]
+        self.assertEqual(merge_motion_windows(flags), [[0.0, 1.0]])
+
+    def test_merge_nearby_windows(self):
+        # 两段活动间隔 1.0s < MERGE_GAP 1.5s，应合并
+        flags = [(0.0, True), (0.5, True), (2.0, True), (2.5, True)]
+        result = merge_motion_windows(flags)
+        self.assertEqual(len(result), 1)
+        self.assertEqual(result[0], [0.0, 2.5])
+
+    def test_separate_windows(self):
+        # 第一段 0-0.5s 活动，中间 1.0-3.5s 无活动（间隔3s > MERGE_GAP 1.5s），第二段 4.0-4.5s 活动
+        flags = [(0.0, True), (0.5, True), (1.0, False), (2.0, False),
+                 (3.0, False), (3.5, False), (4.0, True), (4.5, True)]
+        result = merge_motion_windows(flags)
+        self.assertEqual(len(result), 2)
+
+    def test_filter_short_windows(self):
+        # 0.3s < MIN_DURATION 0.5s，应被过滤
+        flags = [(0.0, True), (0.3, True)]
+        self.assertEqual(merge_motion_windows(flags), [])
+
+    def test_empty_input(self):
+        self.assertEqual(merge_motion_windows([]), [])
+
+
+class TestFallDetection(unittest.TestCase):
+    def test_upright_to_prone_fast(self):
+        # 直立(0s) → 1秒后横躺(1s) → 持续到3s，应检测为摔倒
+        states = [(0.0, "upright"), (1.0, "prone"), (2.0, "prone"), (3.0, "prone")]
+        windows = _find_fall_windows(states)
+        self.assertEqual(len(windows), 1)
+        self.assertEqual(windows[0], (1.0, 3.0))
+
+    def test_slow_prone_not_fall(self):
+        # 直立(0s) → 3秒后才横躺(3s) > TRANSITION_MAX 1.5s，不是摔倒
+        states = [(0.0, "upright"), (3.0, "prone"), (4.0, "prone")]
+        self.assertEqual(_find_fall_windows(states), [])
+
+    def test_prone_without_prior_upright(self):
+        # 视频开头就是横躺，没有直立前置，不算摔倒
+        states = [(0.0, "prone"), (1.0, "prone"), (2.0, "prone")]
+        self.assertEqual(_find_fall_windows(states), [])
+
+    def test_prone_too_short(self):
+        # 横躺只持续 0.5s < SUSTAIN_MIN 1.0s，不算摔倒
+        states = [(0.0, "upright"), (0.5, "prone"), (1.0, "upright")]
+        self.assertEqual(_find_fall_windows(states), [])
+
+    def test_unknown_states_ignored(self):
+        states = [(0.0, "upright"), (0.5, "unknown"), (1.0, "prone"),
+                  (2.0, "prone"), (3.0, "prone")]
+        windows = _find_fall_windows(states)
+        self.assertEqual(len(windows), 1)
+
+
+class TestActivityMerge(unittest.TestCase):
+    def test_merge_same_label(self):
+        samples = [(0.0, "走动", "raw1"), (2.0, "走动", "raw2")]
+        segments = _merge_labeled_samples(samples)
+        self.assertEqual(len(segments), 1)
+        self.assertEqual(segments[0]["label"], "走动")
+        self.assertEqual(segments[0]["start"], 0.0)
+        self.assertEqual(segments[0]["end"], 2.0)
+
+    def test_different_labels_separate(self):
+        samples = [(0.0, "走动", "raw1"), (5.0, "坐下", "raw2")]
+        segments = _merge_labeled_samples(samples)
+        self.assertEqual(len(segments), 2)
+
+    def test_gap_too_large_separates(self):
+        # 间隔 5.0s > MERGE_GAP 3.0s，即使同标签也分开
+        samples = [(0.0, "走动", "raw1"), (5.0, "走动", "raw2")]
+        segments = _merge_labeled_samples(samples)
+        self.assertEqual(len(segments), 2)
+
+
+class TestOllamaParse(unittest.TestCase):
+    def test_exact_label(self):
+        self.assertEqual(_parse_label("走动"), "走动")
+
+    def test_label_with_punctuation(self):
+        self.assertEqual(_parse_label("走动。"), "走动")
+
+    def test_label_in_sentence(self):
+        self.assertEqual(_parse_label("这个人在坐下休息"), "坐下")
+
+    def test_unknown_fallback(self):
+        self.assertEqual(_parse_label("xyz 不存在的标签"), "其他")
+
+    def test_empty_string(self):
+        self.assertEqual(_parse_label(""), "其他")
+
+
+if __name__ == "__main__":
+    unittest.main()