sapegin/jest-cheat-sheet

Features

• Testing Framework Cheat Sheets - Serves as a comprehensive reference and cheat sheet for writing and running test suites with Jest.
• Cheat Sheets - Acts as a concise reference guide for Jest assertions, mocking, and test suite configuration.
• Asynchronous Logic Validation - Guides users on verifying promises and asynchronous patterns to ensure assertions execute correctly.
• Dependency Mocking - Provides detailed strategies for isolating code by substituting real modules and functions with mocks.
• Fake Timers - Provides techniques for replacing native clocks with fake timers to execute delayed logic synchronously.
• Asynchronous Test Handling - Offers a comprehensive guide to verifying promises and time-based logic using asynchronous test patterns.
• Dependency Mocking - Provides detailed examples of substituting real module dependencies with programmable mock implementations.
• Timer Mocks - Shows how to control native timer functions to write synchronous tests for time-dependent logic.
• Value Equality Assertions - Offers a reference for validating data values using strict equality, numeric ranges, and string patterns.
• Exception Assertions - Provides syntax for asserting that functions throw specific errors or match expected exception messages.
• Unit Testing - Provides a collection of syntax examples and best practices for writing isolated unit tests in JavaScript.
• Method Interception Spies - Details how to use spies to track object method calls, getters, and setters without altering original behavior.
• Test Suite Organization - Details the organization of test suites using grouping and lifecycle setup and teardown procedures.
• Call-Stack Interceptors - Details how to capture method invocations and arguments using spy functions to verify behavior.
• Data-Driven Testing - Demonstrates how to use parameterized injection to execute a single test template against multiple input sets.
• Function Call Tracking - Shows how to track function invocations, count calls, and inspect arguments passed to mocks.
• Mock State Resetting - Details how to clear internal call history and restore original function implementations between tests.
• Test Parameterization - Demonstrates how to run the same test logic against multiple data sets using parameterized injection.
• Mock Behavior Configuration - Explains how to define return values and sequential responses for mock functions to simulate dependency outcomes.
• Module Registry Resets - Explains how to flush the cached module registry to prevent state leakage between tests.
• Snapshot Testing - Guides the use of serialized output baselines to detect unexpected changes in components or data.
• Snapshot Diffing - Provides instructions for comparing serialized output snapshots to detect regressions via string diffing.
• Mocking and Assertion References - Provides a technical resource for implementing fake timers, module mocks, and data validation.
• Asynchronous Assertions - Provides guidance on using assertions designed to handle the asynchronous lifecycle and prevent tests from finishing prematurely.
• Test Execution Filtering - Explains how to isolate or exclude specific tests from a run to focus on particular features.
• Front End Development - Quick reference for Jest testing framework syntax.

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