为了避免在其他操作仍在进程中时错误地合并PR，我们需要使用Github Action中的条件检查。具体来说，我们需要在Workflow文件中添加一个on条件，以检测PR的状态，只有在PR被打开但没有被merge时才允许workflow继续执行。这可以通过以下示例代码来实现：

name: Github Action to Build and Test PR

on:
  pull_request:
    types: [opened, synchronize, reopened]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - name: Check if PR is mergeable
        run: |
          if [[ "$(curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
                     -H "Content-Type: application/vnd.github.v3+json" \
                     -X GET $GITHUB_API_URL/pulls/$PR_NUMBER | jq '.mergeable')" == "null" ]]; then
            # If mergeable is null, this means there is a merge conflict
            echo "::error:: PR has merge conflicts, cannot merge"
            exit 1
          elif [[ "$(curl -s -H "Authorization: Bearer $GITHUB_TOKEN" \
                          -H "Content-Type: application/vnd.github.v3+json" \
                          -X GET $GITHUB_API_URL/pulls/$PR_NUMBER | jq '.mergeable')" == "false" ]]; then
            # If mergeable is false, this means there are failing checks
            echo "::error:: PR has failing checks, cannot merge"
            exit 1
          fi
      
      - name: Run tests
        run: pytest

在上述代码中，我们使用了环境变量$PR_NUMBER和$GITHUB_API_URL，需要在Workflow运行时推送这个环境变量，以指定要检查的PR和Github API的url。如果PR有合并冲突或失败的检查，则Workflow将失败并打印出错误信息。如果没有任何问题，Workflow将继续构建和测试PR。