本周的精选文章涵盖了软件开发领域的多个关键方面。文章首先介绍了QA Wolf的自动化端到端测试服务，强调其在提高测试覆盖率和加速QA周期方面的优势。随后，文章深入探讨了系统功能测试的最佳实践，包括单元测试、集成测试、系统测试等。此外，文章还解释了CQRS架构模式和MongoDB的工作原理，并提供了最新的高薪职位招聘信息，涵盖了AI、机器学习等热门领域。最后，文章介绍了ByteByteGo的赞助机会，帮助企业将其产品推广给技术专业人士。

✅ QA Wolf 提供的自动化端到端测试服务，承诺在几周内实现 80% 的自动化 E2E 测试覆盖率，并提供无限的并行测试运行，以及 24 小时的维护和按需测试创建。

💡 系统功能测试是确保软件满足预期、符合用户需求并可靠运行的关键环节。测试方法包括：单元测试、集成测试、系统测试、负载测试和错误测试，以及测试自动化以提高效率。

⚙️ CQRS 架构将写（命令）和读（查询）操作分离，以提高可伸缩性和可维护性。客户端发送命令更新系统状态，更改保存在写入数据库中，并通过事件更新读取模型。查询则从预先计算的读取数据库中检索数据。

💾 MongoDB 是一种流行的 NoSQL 数据库，使用类似 JSON 的格式（BSON）存储数据，并通过分片和复制支持水平扩展。客户端通过 MongoDB 驱动程序连接，查询路由器将查询导向适当的分片，数据分布在多个分片中，每个分片包含处理写入的主节点和用于高可用性和读取扩展的辅助节点。

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This week’s system design refresher:

All-in-One ByteByteGo Technical Interview Prep Kit

Best ways to test system functionality

How CQRS Works

How MongoDB Works

Who’s Hiring Now

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System Design Interview

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Best ways to test system functionality

Testing system functionality is a crucial step in software development and engineering processes.

It ensures that a system or software application performs as expected, meets user requirements, and operates reliably.

Here we delve into the best ways:

Unit Testing: Ensures individual code components work correctly in isolation.

Integration Testing: Verifies that different system parts function seamlessly together.

System Testing: Assesses the entire system's compliance with user requirements and performance.

Load Testing: Tests a system's ability to handle high workloads and identifies performance issues.

Error Testing: Evaluates how the software handles invalid inputs and error conditions.

Test Automation: Automates test case execution for efficiency, repeatability, and error reduction.

Over to you: How do you approach testing system functionality in your software development or engineering projects?

Over to you: what's your company's release process look like?

How CQRS Works?

CQRS (Command Query Responsibility Segregation) separates write (Command) and read (Query) operations for better scalability and maintainability.

Here’s how it works:

1 - The client sends a command to update the system state. A Command Handler validates and executes logic using the Domain Model.

2 - Changes are saved in the Write Database and can also be saved to an Event Store. Events are emitted to update the Read Model asynchronously.

3 - The projections are stored in the Read Database. This database is eventually consistent with the Write Database.

4 - On the query side, the client sends a query to retrieve data.

5 - A Query Handler fetches data from the Read Database, which contains precomputed projections.

6 - Results are returned to the client without hitting the write model or the write database.

Over to you: What else will you add to understand CQRS?

How MongoDB Works?

MongoDB is a popular NoSQL database designed for flexibility, scalability, and high performance. It stores data in a JSON-like format (BSON) and supports horizontal scaling through sharding and replication.

Here’s how it works:

Client application connects via a MongoDB Driver to perform read/write operations.

The Query Router (mongos) acts as a mediator, directing queries to the appropriate shard based on the data’s shard key.

Config servers store metadata and routing information. This helps query routers locate data across shards.

The data is distributed across multiple shards to support horizontal scaling.

Each shard is a replica set that consists of one primary node for handling writes and multiple secondary nodes for high availability and read scaling.

If a primary fails, a secondary is automatically elected to replace it and maintain availability.

Over to you: What else will you add to understand MongoDB’s working better?

Hiring Now

We collaborate with Jobright.ai (an AI job search copilot trusted by 500K+ tech professionals) to curate this job list.

This Week’s High-Impact Roles at Fast-Growing AI Startups

Principal Software Engineer, Linux PCIe Device Drivers at SIMa.ai (San Jose, CA)

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SiMa.ai is a developer of machine learning technology to deliver a software-centric platform.

Senior Software Engineer (C++ Focus) at Inworld AI (Mountain View, CA)

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Inworld AI is an AI framework powering massive consumer applications.

Senior / Staff Software Engineer, Motion Planning at Waabi (San Francisco County, CA)

Yearly: 158000 - 269000

Waabi is an artificial intelligence company that develops autonomous driving technology for the transportation sector.

High Salary SWE Roles this week

Vice President, Engineering - Data Science and Data Engineering Products at NVIDIA (Santa Clara, CA)

Yearly: 480000 - 690000

Senior Software Engineer, Core Infrastructure at Anthropic (Seattle, WA)

Yearly: 320000 - 485000

Distinguished Engineer at Okta (New York)

Yearly: 294000 - 440000

Today’s latest ML positions - hiring now!

Director of Machine Learning Engineering at Workday (Boulder, CO)

Yearly: 307200 - 460800

Sr Director, Machine Learning Engineering at Paypal (San Jose, CA)

Yearly: 232000 - 398750

Staff Machine Learning Engineer - Expansion ML at Square (US)

Yearly: 228700 - 343100

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