The D365 Testing Gap: What We Keep Getting Wrong About Implementation Quality

After years of watching Dynamics 365 implementations succeed and fail, certain patterns become impossible to ignore.

The technology works. Microsoft has built a capable platform. The implementation methodologies are mature. The partner ecosystem is deep with expertise. And yet, a significant number of D365 projects still struggle with quality issues that surface late in the cycle, delay go-lives, and erode confidence in the solution.

The common thread in these troubled projects is rarely the technology itself. It is testing. Or more precisely, the gap between how we think about testing and what D365 implementations actually require.

This piece explores the patterns we see repeatedly across D365 projects and what separates implementations that go smoothly from those that turn into extended firefighting exercises.

Pattern One: Testing Starts Too Late

The most consistent pattern in troubled D365 implementations is simple: testing begins too late in the project timeline.

In a typical implementation, the first few months focus on requirements gathering, solution design, configuration, and development of customisations. Testing enters the picture somewhere around month four or five, when functional consultants begin validating configured processes against requirements.

This timeline creates a structural problem. By month four, significant decisions have already been made. Configurations are locked in. Customisations are built. Integrations are developed based on assumptions about how D365 will behave.

When testing finally begins and issues surface, the project faces an uncomfortable choice: absorb the cost of rework, or accept the defect and plan to address it post go-live. Neither option is good. Rework at this stage is expensive and threatens the timeline. Accepting known defects creates technical debt before the system even launches.

The teams that avoid this trap treat testing as a parallel activity rather than a sequential phase. They validate configurations as they are built, not months later. They test integrations as soon as the interfaces exist, not during the formal integration testing phase. They catch issues when they are cheap to fix rather than expensive to remediate.

This requires having test automation ready early in the project. And that is where most implementations fall short, because building automation from scratch takes months, which means it cannot be ready when you need it most.

Pattern Two: Manual Testing Cannot Keep Pace

D365 Finance and Operations is a large application. A typical implementation touches hundreds of screens, thousands of configuration options, and dozens of interconnected business processes.

Manual testing at this scale is not just slow. It is fundamentally inadequate.

Consider a straightforward Order-to-Cash process: create customer, create sales order, confirm order, pick inventory, pack shipment, post packing slip, create invoice, post invoice, receive payment, apply payment. Each step involves multiple screens and validation points. A thorough manual test of this single process takes 20 to 30 minutes.

Now multiply that across all the variations: different customer types, different payment terms, different shipping methods, different inventory scenarios. Add Procure-to-Pay with its own complexity. Add inventory management, manufacturing, project accounting, whatever modules your implementation includes.

A comprehensive manual regression cycle for D365 F&O commonly requires two to three weeks of dedicated effort from multiple functional consultants. That might be acceptable for a one-time go-live event. It is completely impractical for Microsoft's continuous update model, where you face this testing requirement eight or more times per year.

The maths simply does not work. Either you compress the testing (and accept gaps in coverage), or you consume enormous resources on repetitive manual validation, or you find a way to automate.

Most organisations end up with the first option by default. They run partial regression cycles, focusing on the highest-risk areas and hoping nothing breaks in the areas they did not test. Sometimes that works. Sometimes it results in production issues that cost far more to remediate than proper testing would have cost upfront.

Pattern Three: Customisations Create Blind Spots

Every D365 implementation includes customisations. Extensions, ISV solutions, custom workflows, modified business logic. These customisations deliver business value, but they also create testing blind spots that standard validation approaches miss.

Microsoft tests D365 extensively before each release. But Microsoft tests standard functionality. They cannot test your specific customisations, your particular ISV combinations, your unique integration configurations.

When Microsoft pushes an update that changes how a standard feature behaves, they have validated that the standard feature still works. What they have not validated is whether your customisation that depends on that feature still works. That responsibility falls entirely on you.

The pattern we observe is that customisation-related failures often surface late and unexpectedly. A wave release lands, standard regression tests pass, the update goes to production, and then something breaks in a customised workflow that nobody thought to test. The customisation worked before the update. It was not on the standard test list. Nobody caught it until a user reported a problem.

Addressing this requires maintaining a clear inventory of your customisations and their dependencies on standard D365 functionality. Each customisation needs associated test coverage. When Microsoft announces changes to features your customisations depend on, those become priority testing areas.

This sounds obvious, but in practice most organisations lack a systematic approach to customisation testing. Customisations get built, validated once, and then assumed to be stable. The ongoing testing discipline required to maintain them through continuous updates rarely exists.

Pattern Four: The Skills Gap Is Real

Functional consultants understand D365 business processes deeply. They know how transactions should flow, what validations should occur, and what outcomes indicate success or failure.

Technical resources understand automation tools. They can write scripts, configure test frameworks, and build automated validation.

The problem is these are usually different people, and the translation between them is lossy.

A functional consultant writes a test case: "Verify that a sales order with payment terms Net 30 generates the correct invoice due date." Clear enough in business terms.

A technical resource implements it: locate the sales order form, input customer ID, input item number, input quantity, click confirm, navigate to invoice, extract due date field, compare to expected value. Mechanically correct, but divorced from the business understanding that informed the original requirement.

When the test fails, the technical resource sees a failed element locator or an unexpected value. They may not have the business context to know whether this represents a real problem or an acceptable variation. The functional consultant who could interpret the result was not involved in building the automation and may not understand the technical implementation well enough to diagnose what went wrong.

This gap slows everything down. Test creation requires coordination between functional and technical resources. Test maintenance requires the same coordination. Test result interpretation requires back-and-forth that adds days to what should be simple triage.

The organisations that navigate this most effectively find ways to collapse the gap. They enable functional consultants to participate directly in automation, either through low-code tools or natural language interfaces that do not require programming skills. When the person who understands the business process can also build and maintain the test, the translation losses disappear.

Pattern Five: Test Assets Do Not Travel

Here is a question worth asking: when you complete a D365 implementation and begin the next one, how much of your testing effort carries forward?

For most organisations, the answer is close to zero.

Each implementation starts fresh. New test cases are written. New automation is built (if automation is built at all). The knowledge and assets from previous projects stay with those projects.

This is particularly wasteful given how similar D365 implementations are at their core. Order-to-Cash works the same way across industries. Procure-to-Pay follows the same fundamental process whether you are in manufacturing, retail, or professional services. The module-specific variations matter, but the foundation is consistent.

Implementation partners feel this most acutely. A firm that has delivered 50 D365 F&O implementations has, in theory, accumulated massive expertise in testing these systems. In practice, that expertise lives in the heads of individual consultants rather than in reusable assets. Each new project reinvents what the firm has already learned how to do.

The solution is building test assets that are designed for reusability from the start. Modular components that can be configured for different environments rather than custom scripts tied to a single implementation. Think of it like LEGO blocks: standard pieces that snap together in different combinations rather than custom sculptures that only work in one context.

When test assets travel from project to project, each implementation benefits from accumulated knowledge. The twentieth project is faster and more reliable than the first, because you are building on a foundation rather than starting over.

What Good Looks Like

The implementations that handle testing well share certain characteristics.

They start testing early, validating configurations and customisations as they are built rather than waiting for a formal testing phase.

They automate strategically, focusing on high-risk processes and repetitive regression scenarios where manual testing creates bottlenecks.

They enable functional consultants to participate in automation directly, collapsing the gap between business knowledge and test implementation.

They build test assets that are modular and reusable, treating testing as an investment that compounds over time rather than a cost that resets with each project.

They plan for continuous testing, recognising that Microsoft's update model means testing is an ongoing operational activity rather than a phase that ends at go-live.

None of this requires exotic technology or unlimited budgets. It requires approaching testing as a discipline that deserves the same attention as configuration, development, and training. The organisations that make this shift consistently deliver smoother implementations and more stable production operations.

The Opportunity in Front of Us

The D365 ecosystem has matured significantly over the past several years. Implementation methodologies are well-established. Technical capabilities are proven. The partner community has accumulated deep expertise.

Testing remains an area where many organisations are operating well below their potential. The patterns described here are common, which means the opportunity to improve is equally common.

The question is whether we continue accepting these patterns as inevitable, or whether we invest in approaches that address them systematically.

The tools and methods exist today to close the testing gap. What remains is the decision to prioritise testing as a first-class concern rather than an afterthought that gets compressed when timelines tighten.

The implementations that make that decision consistently outperform those that do not. The evidence is clear enough. The only question is when the rest of the industry will catch up.

Virtuoso combines Robotic Process Automation and Machine Learning to deliver intelligent test automation for Microsoft Dynamics 365. With pre-built components covering core D365 processes and natural language test authoring that enables functional consultants to build automation without coding, Virtuoso helps D365 teams close the testing gap. Learn more about composable D365 testing.