Use Case in Software Testing: How to Turn One Into Test Cases
Every path through a use case becomes at least one test case. A worked bank-transfer example shows the test table, and ISTQB's 2023 and 2025 syllabus changes explain…
Legacy System Modernization
and Migration Services
Vervali modernises systems that still run the business: assessment of what the current system does and what it costs to keep, re-platforming or rebuild, data migration with reconciliation, and regression testing of the old and new systems against the same inputs so you can see they behave the same before you switch. Cutover happens with a rehearsed rollback in place.
150+ clients
450+ projects
275+ engineers
15+ years
ISO/IEC 17025:2017Accredited testing laboratory
CMMI Maturity Level 3The process is written down and repeats
ISO 9001:2015Quality management
ISO/IEC 27001Information security
How We Prove a Migration Is Safe
Your system works and you cannot afford to break it. Four checks prove the new one behaves the same before you switch.
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01
Parallel Run
Old and new systems process the same live inputs side by side for an agreed window. Nobody switches until the outputs match, and the window length is signed before it starts.
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02
Data Reconciliation
Counts, balances, duplicates and records that would not map, in a report you sign before cutover. History that was never valid is named, not silently dropped.
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03
Regression Comparison
The same inputs run through both systems and every difference is explained or fixed, using our application testing method. That is how you see they behave the same before you switch.
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04
Rehearsed Rollback
The rollback is timed in rehearsal, not invented on the night. If the comparison fails, you stay on the system that still works. The decision to abort is a decision, not a panic.
See the old and new systems agree before you switch.
Book a ReviewThe Four Approaches, and When Each Is Right
Each approach has a cost, a fix and something it leaves behind. The quote names which one you are buying.
Rehost
The same software on new infrastructure. It fixes the hardware problem and none of the software problems. Right when the hardware is the risk and the code is sound.
Re-Platform
A new runtime, database or hosting shape without rewriting the business rules. Cloud-native targets on AWS and Azure, or the clouds you already run.
Refactor
Outdated applications split into services and containers, so you gain agility without a full rewrite. Right when the rules are valuable and the structure is the problem.
Rebuild
The system is replaced when it cannot carry the next process. ERP and CRM cores through ERP and CRM development, custom cores through custom software development.
Data Migration and Reconciliation
This is the part that actually goes wrong, so it is the part we prove in writing.
Field Mapping
Fields where the old system's meaning is not the new system's meaning are mapped with the people who use them, not guessed from column names.
What Moves and What Is Archived
Records that were never valid, and history that is archived rather than moved, are decided and listed before the move. Backups and an audit trail sit alongside.
The Reconciliation Report
Counts, balances, duplicates found and records that would not map. You sign that report before cutover, not after the first week in production.
Vendor Lock-In and Proprietary Technology
When the vendor no longer supports the system or will not let you leave, the first job is getting your data out.
Extraction Without an Export
Data extraction where there is no export function, and rewriting the interface rather than the whole system.
What We Could Not See
We do not pretend every closed box has a clean dump. Anything we could not reach goes on the risk register with an owner.
The Target Comes Second
Open source or a cloud target is a later choice, made once the data you own is actually in your hands.
Compliance and Security After the Move
A migration resets the evidence, and an auditor will ask. Controls are re-established, not assumed.
Access, Logging and Retention
Access control, audit logging, retention and any certification scope the old system carried are rebuilt and tested on the new one. GDPR and HIPAA are named when they apply to you.
Evidence for the Auditor
Evidence packs through our compliance testing practice when that pass is in the quote. Vervali tests SOC 2 readiness and is not itself SOC 2 certified, and runs an ISO/IEC 27001 certified management system.
When the Target Is Cloud
Cloud execution of the move runs through cloud migration and modernisation and cloud application development, with the same reconciliation and rollback.
The Cost of Doing Nothing
Year two of doing nothing is still a number, even if it never arrives as an invoice.
Maintenance and Skills
Maintenance on ageing code, and a shrinking pool of people who can still work on it. Every leaver takes knowledge the system depends on.
Blocked Integrations
The next integration, product or channel the business wants and the old system cannot take, or takes only at a cost that grows each year.
Unpatched Exposure
Software that can no longer be patched is a compliance exposure. The assessment puts the cost of keeping the stack next to the cost of the first move, with no invented savings figure.
Proof From Delivery
Core platforms that still ran the business while they changed.
Two private-sector banks · lending platforms
60% faster loan processing and 50% less agent onboarding time, with the compliance the engagement required. Platforms like that do not move in one weekend: assessment, a sequence, data that still balances and a timed rollback are how a core that runs the business is allowed to change.
60% faster loan processing50% less agent onboarding timeManufacturer · sales-operations platform
40% less manual stock reconciliation on a sales-operations platform. That is what changes when the old record and the new process finally agree. A cutover without that reconciliation is how month-end becomes a war room.
40% less manual stock reconciliationFrequently Asked Questions
A system that still runs the business can also be costly to keep, hard to hire for, and unable to take the next integration or the next security patch. Modernisation keeps the outcomes your teams rely on and drops the cost and risk of keeping the old code. It starts with an assessment of what the system does today and what it costs to keep, so the decision rests on numbers rather than fear.
Rehost, re-platform, refactor and rebuild. Rehost moves the same software onto new infrastructure. Re-platform changes the runtime or hosting without rewriting the rules. Refactor splits the application. Rebuild replaces it. Rehosting fixes the hardware problem and none of the software problems. The quote names which one you are buying. A lift and shift sold as modernisation is the disappointment we refuse to label as done.
We do not sell a guarantee of zero disruption. We prove the move is safe before you switch: a parallel run, data reconciliation on counts and balances, regression comparison of old and new against the same inputs, and a rehearsed rollback that has been timed. The decision to abort is a decision, not a panic. Application testing is the method for that comparison.
The reconciliation report. Counts, balances, duplicates found, records that would not map, and what was archived rather than moved. Backups and an audit trail sit in that pack. You sign it before cutover. Field mapping is where the old meaning is not the new meaning. Invalid history is named, not silently dropped. That report is how you see the data arrived intact, not a go-live email.
Yes. Cloud-native targets are part of the offer, on AWS and Azure or the clouds you already run. Rehosting onto a cloud account without changing the software is still a rehost, so the plan says which approach you are buying. Where the quote includes the build, it runs through our cloud application development and cloud migration and modernisation teams, with the same reconciliation and rollback.
Then the job is extraction where there is no export, and rewriting the interface rather than the whole system. We do not pretend every closed box has a clean dump. What we could not see goes on the risk register. Open-source or a cloud target is a later choice, after the data you own is actually yours. Book a modernization review once that constraint is written down.
Access control, audit logging, retention and any certification scope the old system carried have to be re-established. A migration resets the evidence and an auditor will ask. GDPR and HIPAA are named when they apply. Vervali tests a client's systems for SOC 2 readiness and is not itself SOC 2 certified. Compliance testing is the evidence pack when that pass is in the quote.
It follows the size of the estate, how much data moves, whether the approach is rehost or rebuild, and how long the parallel run must last before you will sign. We do not publish a fixed week count, because the honest answer depends on those four things. Time starts when we can see the system and the people who still know it, and the quote after the assessment names the weeks.
Price follows the approach, the data volume, the parallel-run window and the test pack. Clutch lists Vervali at $25 to $49 per hour. We quote after a modernization review or a free assessment of one system, not as a published project total. Doing nothing still costs maintenance, scarce skills and unpatched risk. That number is yours. The engagement number is the quote.
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