Simple Aged Cache (Project)

Video1: Testing Fundamentals

Why Testing is Important

• Test Early and Often: Testing should occur early and frequently in software development to ensure high quality and testability.
• User-Centered Testing: Testing ensures the product meets user expectations and requirements, facilitating clear communication among stakeholders.

Types of Testing

1. Unit Tests:

   • Low-level tests that validate individual methods or functions.
   • Focus on different paths, conditions, and logic within a single code unit.

2. Integration Tests:

   • Checks interactions between different modules or components.
   • Examples include API calls, database connections, and inter-module communication.

3. Acceptance Tests:

   • High-level tests that validate software from the user’s perspective.
   • Typically derived from user stories or requirements, such as user registration functionality.

Testing Approaches

• Outside-In Testing:

  • Starts with acceptance tests and gradually dives into unit tests.
  • Suitable for applications like web apps with clear configurations and CRUD operations.

• Inside-Out Testing:

  • Starts with unit tests and gradually expands to integration and acceptance tests.
  • Suitable for backend systems with complex business logic.

Code Coverage

• Statement Coverage: Ensures each method is tested.
• Branch Coverage: Tests different method call chains.
• Conditional Coverage: Tests if-else logic and guard conditions.
• Path Coverage: Ensures coverage of system execution flow, including edge cases.

Refactoring

• Importance of Refactoring:

  • Ensures code evolves with changing requirements and improves over time.
  • Follows the “Red-Green-Refactor” cycle: write tests first, write code to pass tests, refactor for improved design.

• Related Books:

  • Refactoring
  • Design Patterns
  • Refactoring to Patterns

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Video2: Test Doubles in Testing

In software engineering, Test Doubles are crucial concepts that help effectively conduct unit, integration, and acceptance testing.

• Stub:

  • Replaces real components, returns predefined responses.

• Mock:

  • Provides programmable behavior to verify interactions in tests.

• Spy:

  • Records actual operations for subsequent verification.

• Fake:

  • Substitute implementation used to enhance test efficiency.

• Dummy:

  • Placeholder typically used to satisfy method parameter requirements.

These Test Doubles aid in isolation and mocking during testing, ensuring focused and speedy tests that verify code behavior and interactions.

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Video3: Simple Aged Cache Project Launch Video

To kickstart the “Simple Aged Cache” assignment project, here’s an overview of key steps and technology stack:

1. Project Download and Setup:

   • Download project code from the provided GitHub URL.
   • Review the README for basic project information and setup guidelines.

2. Project Structure and Setup:

   • Extract downloaded project files and place them in a suitable working directory, e.g., workspace folder in the user directory.

3. Environment Setup:

   • Use command-line tools like Terminal to execute Gradle commands within the project directory.
   • Gradle serves as the build tool, managing dependencies and executing the test suite with commands like gradlew clean build.

4. Integrated Development Environment (IDE):

   • Recommend using IntelliJ IDEA as the primary IDE.
   • Import the project into IntelliJ, ensuring correct JDK and Gradle environment settings.

5. Continuous Integration:

   • The project may include GitHub Actions configuration files (e.g., build.yml) for continuous integration and automated builds on GitHub.

6. Technology Stack and Tools:

   • Use JVM technology stack, with options to implement in Java or Kotlin.
   • Gradle manages project dependencies and build processes.
   • JUnit serves as the testing framework for writing and executing unit tests.

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Project: Simple Aged Cache Project Overview

The Simple Aged Cache project is designed as an exercise to introduce modern software engineering practices, particularly focusing on test-driven development (TDD). It serves as an educational tool to understand the fundamentals of building scalable software systems, particularly those leveraging big data concepts.

Background

Initially developed in the early 2000s at a telecommunications company, the Simple Aged Cache has evolved into a learning tool for software engineering interviews. It emphasizes TDD and has been used successfully in interview processes at various companies, including Gnip and Twitter.

Project Details

The project aims to implement a basic cache system with the following requirements:

• Constructor Variations: Includes constructors with and without a Clock parameter.
• Method Definitions: Key methods such as put, isEmpty, size, and get are defined to manage cache entries.
• Exercise Objectives: Participants are tasked with making the provided tests pass, exploring concepts like ExpirableEntry and avoiding built-in collection classes.

Implementation Choices

Participants are encouraged to explore different implementations using Java and Kotlin, and to consider the use of an inner class for ExpirableEntry instead of traditional collection classes.

Learning Objectives

• Understanding the importance of TDD in software development.
• Implementing basic data structures and algorithms for caching purposes.
• Exploring alternative approaches to common programming tasks.

Getting Started

To begin working on the Simple Aged Cache project:

1. Download the Codebase: Visit Simple Aged Cache to obtain the project files.

2. Setup Environment: Ensure you have Java or Kotlin installed, along with Gradle for managing dependencies and building the project.

3. Explore and Implement: Follow the instructions provided in the README to start implementing and testing your solution.

4. Feedback and Improvement: Use TDD principles to iteratively improve your implementation, aiming to pass the provided test cases.

Conclusion

The Simple Aged Cache project not only serves as a practical exercise in software engineering but also highlights the iterative nature of software development through TDD. By focusing on building scalable and maintainable systems, participants gain valuable insights into modern software architecture principles.

For more details, refer to the Simple Aged Cache Workshop provided by Initial Capacity.

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