update unit testing CI rules

.github/workflows/build.yml

@@ -0,0 +1,38 @@
+name: Build
+
+on: 
+  pull_request:
+    types: [synchronize, labeled]
+
+jobs:
+  build:
+    name: Build and Test Colossal-AI
+    if: |
+        github.event.pull_request.draft == false && 
+        (github.base_ref == 'main' || github.base_ref == 'develop') && 
+        github.event.pull_request.base.repo.full_name == 'hpcaitech/ColossalAI' &&
+        contains( github.event.pull_request.labels.*.name, 'Run Build and Test')
+    runs-on: [self-hosted, gpu]
+    container:
+      image: nvcr.io/nvidia/pytorch:21.07-py3
+      options: --gpus all --rm --ipc=host -v /data/scratch/cifar-10:/data/scratch/cifar-10
+    timeout-minutes: 20
+    steps:
+      - name: Setup Environment
+        run: |
+          export https_proxy=http://172.17.0.1:7890 http_proxy=http://172.17.0.1:7890 all_proxy=socks5://172.17.0.1:7890
+      - name: Install dependencies
+        run: |
+          pip config set global.index-url https://pypi.tuna.tsinghua.edu.cn/simple
+          pip install -U pip setuptools wheel --user
+          pip install pytest tensorboard deepspeed apex
+      - uses: actions/checkout@v2
+      - name: Install Colossal-AI      
+        run: |
+          pip install -r requirements/requirements.txt
+          pip install -v --no-cache-dir .
+      - name: Unit Testing
+        run: |
+          pytest tests
+        env:
+          DATA: /data/scratch/cifar-10