What is Regression Testing during Dynamics 365 upgrades?

Regression testing during a Dynamics 365 upgrade is the process of verifying that existing business functionality, customizations, integrations, security, automation, and user processes still work correctly after the platform or application has been upgraded. The key principle is: An upgrade should introduce new capabilities without unintentionally breaking existing business processes. This becomes particularly important in Dynamics 365 because an implementation may contain many interconnected components. Why regression testing is necessary A Dynamics 365 environment may contain: Dynamics 365 ↓ Dataverse ↓ Plugins ↓ JavaScript ↓ Power Automate ↓ Power BI ↓ Azure integrations ↓ External applications A platform upgrade can potentially affect behavior across these layers. For example: Dynamics 365 Upgrade ↓ Existing JavaScript behaves differently ↓ Form validation fails ↓ Record cannot be saved ↓ Business process disrupted The upgrade itself may be successful technically, but the business application can still be broken. What should be regression tested? An expert regression strategy should go beyond simply opening a few forms. 1. Core business processes Test critical end-to-end processes such as: Lead ↓ Opportunity ↓ Quote ↓ Order ↓ Invoice or organization-specific processes. The question is: Can users still complete their critical business journeys? 2. Forms and views Validate: Form loading Field visibility Business rules Required fields Tabs Subgrids Quick views Views Command bar behavior Related records 3. JavaScript Custom JavaScript is a common regression area. Test: OnLoad OnChange OnSave Ribbon/command logic Web API calls Form notifications Dynamic field behavior Older APIs or unsupported patterns can become problematic during platform evolution. 4. Plugins Test: Pre-validation plugins Pre-operation plugins Post-operation plugins Synchronous execution Asynchronous execution Plugin dependencies Exception handling Transaction behavior For example: Create Account ↓ Plugin executes ↓ Creates related record ↓ Integration triggered The complete chain should be tested. 5. Power Automate Regression testing should include: Cloud flows Trigger execution Dataverse triggers Connection references Environment variables Approval flows Error handling Retry behavior Child flows Integration connectors A flow may technically remain enabled while failing because of changed configuration or connection behavior. 6. Integrations This is one of the highest-risk areas. Test integrations with: ERP Azure services APIs SQL Server SharePoint External CRM systems Data warehouses Middleware For example: Dynamics 365 ↓ Integration API ↓ ERP ↓ Response ↓ Dynamics 365 Both directions should be tested where applicable. 7. Security Regression testing should verify that users still have the correct access. Test: Security roles Business units Teams Record ownership Sharing Field-level security Hierarchical access Administrative permissions A particularly dangerous regression is: Functionality works, but a user can now see data they shouldn't. That makes security testing as important as functional testing. Regression Testing Strategy A mature Dynamics 365 upgrade project normally follows multiple test stages. Development ↓ Unit Testing ↓ System/Functional Testing ↓ Integration Testing ↓ Regression Testing ↓ UAT ↓ Production ↓ Post-Go-Live Validation Regression testing isn't necessarily a single isolated test phase. It should be incorporated throughout the upgrade lifecycle. Risk-based regression testing You don't necessarily need to test every single feature manually after every upgrade. Instead, classify functionality based on risk. Critical Examples: Order processing Financial integration Customer creation Revenue processes Security External integrations These require comprehensive testing. Medium Examples: Secondary workflows Reporting Non-critical automation Low Examples: Rarely used administrative functionality Cosmetic customizations This gives better coverage without making testing unnecessarily expensive. Automated regression testing For mature implementations, automated testing can significantly reduce upgrade risk. Potential approaches include: Power Platform Test Engine Playwright/Selenium-style UI automation where appropriate API-based tests Automated integration tests Power Automate validation Solution validation CI/CD pipeline checks A mature process might look like: New Dynamics Upgrade ↓ Deploy to Test ↓ Automated Regression Suite ↓ Functional Regression ↓ Integration Regression ↓ Security Validation ↓ UAT ↓ Production Regression Testing vs UAT These are not identical. Regression Testing Question: Did the upgrade break anything that previously worked? User Acceptance Testing Question: Does the upgraded system satisfy the business requirements and user expectations? For example: Regression: Existing opportunity process still works. UAT: Sales team confirms the upgraded opportunity process supports their business requirements. Both are important. Regression Test Case Example Suppose an organization has an automated opportunity process. A regression test might be: 1. Create Account 2. Create Contact 3. Create Opportunity 4. Add Products 5. Update Opportunity 6. Move Opportunity through business process 7. Trigger Power Automate flow 8. Verify plugin execution 9. Verify ERP integration 10. Verify security 11. Verify reporting The goal isn't merely to confirm that the Opportunity table opens. The goal is to verify the entire business transaction chain. Expert-level interview answer Regression testing during a Dynamics 365 upgrade is the systematic validation that existing functionality continues to operate correctly after the platform, application, solutions, or underlying components have changed. It should cover critical business processes, Dataverse customizations, plugins, JavaScript, Power Automate flows, integrations, security, reports, and user journeys. A mature regression strategy is risk-based and combines automated testing with targeted functional and integration testing, followed by UAT and post-production validation. Quick Interview Revision Question Core Concept Connection References Logical abstraction for connector connections in Power Platform solutions Azure Bicep Declarative Azure Infrastructure-as-Code language Records Data-oriented types with value-based equality; can be class or struct Structs Value types intended primarily for small value semantics Dynamics 365 Web API REST/OData interface for Dataverse/Dynamics 365 interaction Regression Testing Ensures existing functionality isn't broken by an upgrade The deeper connection between these topics These five questions actually cover five important enterprise-development areas: Power Platform ↓ ALM & Connections ↓ Connection References Azure ↓ Infrastructure as Code ↓ Bicep C# ↓ Type Design ↓ Records & Structs Dynamics 365 ↓ Integration/API ↓ Web API Dynamics 365 ALM ↓ Upgrade Assurance ↓ Regression Testing That makes them particularly good interview questions for Power Platform, Dynamics 365, Azure, and .NET professionals.