V Model - Classical Lifecycle

• Requirements Analysis -- Business requirements document or business requirements specification
• System Design -- Systems requirements specifications / functional specification
• Architecture Design -- High level design
• Module Design - Low-level design

Shift Left (Courtesy BMC)

Shift left is a software testing approach where software testing is performed (moved or shifted) to the left / earlier in the Life-cycle. This basically is "Test Early and Test Often".

• In the Traditional Model, requirements and design happen to the left, and testing of those requirements to the right. As the project progresses, the testing effort increases. 
• Consequently later the defects are found, the costlier it becomes to fix those bugs

• In Shift Left, testing is performed during early stages by engaging early in the project lifecycle. 

JavaScript Object Hierarchy - CERN European Particle Physics Laboratory

TXR Test Planning & Execution

7 Principles of Software Testing...