Define the Testing Pyramid and explain its fundamental purpose in modern software development.

Describe Unit Tests in detail, covering their characteristics, typical coverage, and why they form the largest portion of a test suite. Emphasize their role in immediate feedback and granular code quality.

Explain Integration Tests, detailing their position in the Testing Pyramid, what they test (e.g., component interactions, external services), their relative speed, and their importance in validating interfaces and collaborations.

Detail End-to-End (E2E) Tests, including their characteristics (e.g., slow execution, brittleness, real user scenarios, UI interactions), what they cover, and why they represent the smallest portion of the test suite. Discuss their value and drawbacks.

A team currently has 90% slow, brittle end-to-end UI tests and very few unit tests, leading to hours-long CI processes. Explain why adhering to Testing Pyramid principles is crucial for improving CI speed, developer productivity, and software quality in this situation. Conclude with specific recommendations on how the team can begin to shift their testing strategy to align with the Testing Pyramid.