diff --git a/app/services/video.py b/app/services/video.py
index e3a5abe..011f8f2 100644
--- a/app/services/video.py
+++ b/app/services/video.py
@@ -1,4 +1,5 @@
 import glob
+import itertools
 import os
 import random
 import gc
@@ -31,15 +32,19 @@ from app.services.utils import video_effects
 from app.utils import utils
 
 class SubClippedVideoClip:
-    def __init__(self, file_path, start_time, end_time, width=None, height=None):
+    def __init__(self, file_path, start_time=None, end_time=None, width=None, height=None, duration=None):
         self.file_path = file_path
         self.start_time = start_time
         self.end_time = end_time
         self.width = width
         self.height = height
+        if duration is None:
+            self.duration = end_time - start_time
+        else:
+            self.duration = duration
 
     def __str__(self):
-        return f"SubClippedVideoClip(file_path={self.file_path}, start_time={self.start_time}, end_time={self.end_time}, width={self.width}, height={self.height})"
+        return f"SubClippedVideoClip(file_path={self.file_path}, start_time={self.start_time}, end_time={self.end_time}, duration={self.duration}, width={self.width}, height={self.height})"
 
 
 audio_codec = "aac"
@@ -131,7 +136,7 @@ def combine_videos(
     aspect = VideoAspect(video_aspect)
     video_width, video_height = aspect.to_resolution()
 
-    clip_files = []
+    processed_clips = []
     subclipped_items = []
     video_duration = 0
     for video_path in video_paths:
@@ -144,7 +149,7 @@ def combine_videos(
 
         while start_time < clip_duration:
             end_time = min(start_time + max_clip_duration, clip_duration)            
-            if clip_duration - start_time > max_clip_duration:
+            if clip_duration - start_time >= max_clip_duration:
                 subclipped_items.append(SubClippedVideoClip(file_path= video_path, start_time=start_time, end_time=end_time, width=clip_w, height=clip_h))
             start_time = end_time    
             if video_concat_mode.value == VideoConcatMode.sequential.value:
@@ -171,7 +176,7 @@ def combine_videos(
             if clip_w != video_width or clip_h != video_height:
                 clip_ratio = clip.w / clip.h
                 video_ratio = video_width / video_height
-                logger.debug(f"resizing to {video_width}x{video_height}, source: {clip_w}x{clip_h}, ratio: {clip_ratio:.2f}, target ratio: {video_ratio:.2f}")
+                logger.debug(f"resizing clip, source: {clip_w}x{clip_h}, ratio: {clip_ratio:.2f}, target: {video_width}x{video_height}, ratio: {video_ratio:.2f}")
                 
                 if clip_ratio == video_ratio:
                     clip = clip.resized(new_size=(video_width, video_height))
@@ -221,28 +226,39 @@ def combine_videos(
             
             close_clip(clip)
         
-            clip_files.append(clip_file)
+            processed_clips.append(SubClippedVideoClip(file_path=clip_file, duration=clip.duration, width=clip_w, height=clip_h))
             video_duration += clip.duration
             
         except Exception as e:
             logger.error(f"failed to process clip: {str(e)}")
-            
+    
+    # loop processed clips until the video duration matches or exceeds the audio duration.
+    if video_duration < audio_duration:
+        logger.warning(f"video duration ({video_duration:.2f}s) is shorter than audio duration ({audio_duration:.2f}s), looping clips to match audio length.")
+        base_clips = processed_clips.copy()
+        for clip in itertools.cycle(base_clips):
+            if video_duration >= audio_duration:
+                break
+            processed_clips.append(clip)
+            video_duration += clip.duration
+        logger.info(f"video duration: {video_duration:.2f}s, audio duration: {audio_duration:.2f}s, looped {len(processed_clips)-len(base_clips)} clips")
+     
     # merge video clips progressively, avoid loading all videos at once to avoid memory overflow
     logger.info("starting clip merging process")
-    if not clip_files:
+    if not processed_clips:
         logger.warning("no clips available for merging")
         return combined_video_path
     
     # if there is only one clip, use it directly
-    if len(clip_files) == 1:
+    if len(processed_clips) == 1:
         logger.info("using single clip directly")
-        shutil.copy(clip_files[0], combined_video_path)
-        delete_files(clip_files)
+        shutil.copy(processed_clips[0].file_path, combined_video_path)
+        delete_files(processed_clips)
         logger.info("video combining completed")
         return combined_video_path
     
     # create initial video file as base
-    base_clip_path = clip_files[0]
+    base_clip_path = processed_clips[0].file_path
     temp_merged_video = f"{output_dir}/temp-merged-video.mp4"
     temp_merged_next = f"{output_dir}/temp-merged-next.mp4"
     
@@ -250,13 +266,13 @@ def combine_videos(
     shutil.copy(base_clip_path, temp_merged_video)
     
     # merge remaining video clips one by one
-    for i, clip_path in enumerate(clip_files[1:], 1):
-        logger.info(f"merging clip {i}/{len(clip_files)-1}")
+    for i, clip in enumerate(processed_clips[1:], 1):
+        logger.info(f"merging clip {i}/{len(processed_clips)-1}, duration: {clip.duration:.2f}s")
         
         try:
             # load current base video and next clip to merge
             base_clip = VideoFileClip(temp_merged_video)
-            next_clip = VideoFileClip(clip_path)
+            next_clip = VideoFileClip(clip.file_path)
             
             # merge these two clips
             merged_clip = concatenate_videoclips([base_clip, next_clip])
@@ -286,6 +302,7 @@ def combine_videos(
     os.rename(temp_merged_video, combined_video_path)
     
     # clean temp files
+    clip_files = [clip.file_path for clip in processed_clips]
     delete_files(clip_files)
             
     logger.info("video combining completed")
@@ -511,8 +528,7 @@ def preprocess_video(materials: List[MaterialInfo], clip_duration=4):
             # Output the video to a file.
             video_file = f"{material.url}.mp4"
             final_clip.write_videofile(video_file, fps=30, logger=None)
-            final_clip.close()
-            del final_clip
+            close_clip(clip)
             material.url = video_file
             logger.success(f"image processed: {video_file}")
     return materials
\ No newline at end of file
diff --git a/app/utils/utils.py b/app/utils/utils.py
index 0672681..7efb521 100644
--- a/app/utils/utils.py
+++ b/app/utils/utils.py
@@ -1,6 +1,7 @@
 import json
 import locale
 import os
+from pathlib import Path
 import threading
 from typing import Any
 from uuid import uuid4
@@ -226,4 +227,4 @@ def load_locales(i18n_dir):
 
 
 def parse_extension(filename):
-    return os.path.splitext(filename)[1].strip().lower().replace(".", "")
+    return Path(filename).suffix.lower().lstrip('.')
diff --git a/test/README.md b/test/README.md
new file mode 100644
index 0000000..adfb4ad
--- /dev/null
+++ b/test/README.md
@@ -0,0 +1,39 @@
+# MoneyPrinterTurbo Test Directory
+
+This directory contains unit tests for the **MoneyPrinterTurbo** project.
+
+## Directory Structure
+
+- `services/`: Tests for components in the `app/services` directory  
+  - `test_video.py`: Tests for the video service  
+  - `test_task.py`: Tests for the task service  
+
+## Running Tests
+
+You can run the tests using Python’s built-in `unittest` framework:
+
+```bash
+# Run all tests
+python -m unittest discover -s test
+
+# Run a specific test file
+python -m unittest test/services/test_video.py
+
+# Run a specific test class
+python -m unittest test.services.test_video.TestVideoService
+
+# Run a specific test method
+python -m unittest test.services.test_video.TestVideoService.test_preprocess_video
+````
+
+## Adding New Tests
+
+To add tests for other components, follow these guidelines:
+
+1. Create test files prefixed with `test_` in the appropriate subdirectory
+2. Use `unittest.TestCase` as the base class for your test classes
+3. Name test methods with the `test_` prefix
+
+## Test Resources
+
+Place any resource files required for testing in the `test/resources` directory.
\ No newline at end of file
diff --git a/test/__init__.py b/test/__init__.py
new file mode 100644
index 0000000..584e3c9
--- /dev/null
+++ b/test/__init__.py
@@ -0,0 +1 @@
+# Unit test package for test
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diff --git a/test/resources/8.png b/test/resources/8.png
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diff --git a/test/services/__init__.py b/test/services/__init__.py
new file mode 100644
index 0000000..a07aa62
--- /dev/null
+++ b/test/services/__init__.py
@@ -0,0 +1 @@
+# Unit test package for services
\ No newline at end of file
diff --git a/test/services/test_task.py b/test/services/test_task.py
new file mode 100644
index 0000000..8b241a9
--- /dev/null
+++ b/test/services/test_task.py
@@ -0,0 +1,66 @@
+import unittest
+import os
+import sys
+from pathlib import Path
+
+# add project root to python path
+sys.path.insert(0, str(Path(__file__).parent.parent.parent))
+
+from app.services import task as tm
+from app.models.schema import MaterialInfo, VideoParams
+
+resources_dir = os.path.join(os.path.dirname(os.path.dirname(__file__)), "resources")
+
+class TestTaskService(unittest.TestCase):
+    def setUp(self):
+        pass
+    
+    def tearDown(self):
+        pass
+    
+    def test_task_local_materials(self):
+        task_id = "00000000-0000-0000-0000-000000000000"
+        video_materials=[]
+        for i in range(1, 4):
+            video_materials.append(MaterialInfo(
+                provider="local",
+                url=os.path.join(resources_dir, f"{i}.png"),
+                duration=0
+            ))
+
+        params = VideoParams(
+            video_subject="金钱的作用",
+            video_script="金钱不仅是交换媒介，更是社会资源的分配工具。它能满足基本生存需求，如食物和住房，也能提供教育、医疗等提升生活品质的机会。拥有足够的金钱意味着更多选择权，比如职业自由或创业可能。但金钱的作用也有边界，它无法直接购买幸福、健康或真诚的人际关系。过度追逐财富可能导致价值观扭曲，忽视精神层面的需求。理想的状态是理性看待金钱，将其作为实现目标的工具而非终极目的。",
+            video_terms="money importance, wealth and society, financial freedom, money and happiness, role of money",
+            video_aspect="9:16",
+            video_concat_mode="random",
+            video_transition_mode="None",
+            video_clip_duration=3,
+            video_count=1,
+            video_source="local",
+            video_materials=video_materials,
+            video_language="",
+            voice_name="zh-CN-XiaoxiaoNeural-Female",
+            voice_volume=1.0,
+            voice_rate=1.0,
+            bgm_type="random",
+            bgm_file="",
+            bgm_volume=0.2,
+            subtitle_enabled=True,
+            subtitle_position="bottom",
+            custom_position=70.0,
+            font_name="MicrosoftYaHeiBold.ttc",
+            text_fore_color="#FFFFFF",
+            text_background_color=True,
+            font_size=60,
+            stroke_color="#000000",
+            stroke_width=1.5,
+            n_threads=2,
+            paragraph_number=1
+        )
+        result = tm.start(task_id=task_id, params=params)
+        print(result)
+    
+
+if __name__ == "__main__":
+    unittest.main() 
\ No newline at end of file
diff --git a/test/services/test_video.py b/test/services/test_video.py
new file mode 100644
index 0000000..d204acc
--- /dev/null
+++ b/test/services/test_video.py
@@ -0,0 +1,85 @@
+
+import unittest
+import os
+import sys
+from pathlib import Path
+from moviepy import (
+    VideoFileClip,
+)
+# add project root to python path
+sys.path.insert(0, str(Path(__file__).parent.parent.parent))
+from app.models.schema import MaterialInfo
+from app.services import video as vd
+from app.utils import utils
+
+resources_dir = os.path.join(os.path.dirname(os.path.dirname(__file__)), "resources")
+
+class TestVideoService(unittest.TestCase):
+    def setUp(self):
+        self.test_img_path = os.path.join(resources_dir, "1.png")
+    
+    def tearDown(self):
+        pass
+    
+    def test_preprocess_video(self):
+        if not os.path.exists(self.test_img_path):
+            self.fail(f"test image not found: {self.test_img_path}")
+        
+        # test preprocess_video function
+        m = MaterialInfo()
+        m.url = self.test_img_path
+        m.provider = "local"
+        print(m)
+        
+        materials = vd.preprocess_video([m], clip_duration=4)
+        print(materials)
+        
+        # verify result
+        self.assertIsNotNone(materials)
+        self.assertEqual(len(materials), 1)
+        self.assertTrue(materials[0].url.endswith(".mp4"))
+        
+        # moviepy get video info
+        clip = VideoFileClip(materials[0].url)
+        print(clip)
+        
+        # clean generated test video file
+        if os.path.exists(materials[0].url):
+            os.remove(materials[0].url)
+    
+    def test_wrap_text(self):
+        """test text wrapping function"""
+        try:
+            font_path = os.path.join(utils.font_dir(), "STHeitiMedium.ttc")
+            if not os.path.exists(font_path):
+                self.fail(f"font file not found: {font_path}")
+                
+            # test english text wrapping
+            test_text_en = "This is a test text for wrapping long sentences in english language"
+            
+            wrapped_text_en, text_height_en = vd.wrap_text(
+                text=test_text_en,
+                max_width=300,
+                font=font_path,
+                fontsize=30
+            )
+            print(wrapped_text_en, text_height_en)
+            # verify text is wrapped
+            self.assertIn("\n", wrapped_text_en)
+            
+            # test chinese text wrapping
+            test_text_zh = "这是一段用来测试中文长句换行的文本内容，应该会根据宽度限制进行换行处理"
+            wrapped_text_zh, text_height_zh = vd.wrap_text(
+                text=test_text_zh,
+                max_width=300,
+                font=font_path,
+                fontsize=30
+            )   
+            print(wrapped_text_zh, text_height_zh)
+            # verify chinese text is wrapped
+            self.assertIn("\n", wrapped_text_zh)
+        except Exception as e:
+            self.fail(f"test wrap_text failed: {str(e)}")
+
+if __name__ == "__main__":
+    unittest.main() 
\ No newline at end of file