Behavior-driven development (BDD), or behavior-driven development methodology, offers an approach to software testing that helps bring the perspectives of the technical and business teams closer together. With BDD, these groups can collaborate more effectively, define requirements more precisely, and build applications that meet real user needs.
In the financial industry, software testing plays a key role in the development of IT systems, supporting reliability, regulatory compliance, and security. Collaboration between technical and business teams is exceptionally important in this case and is paramount to ensuring that financial applications perform and meet user expectations.
Behavior-Driven Development (BDD) is a software development methodology designed to enhance collaboration between developers, testers, and business stakeholders. By focusing on how a system behaves from the user’s perspective, BDD bridges the gap between technical teams and non-technical stakeholders. It builds on the foundation of Test-Driven Development (TDD) but shifts the focus from technical correctness to ensuring that a system’s behavior aligns with business objectives and user expectations.
At the core of BDD is the practice of writing scenarios that describe the desired system behavior in specific contexts. These scenarios, often written in plain-text format using Gherkin syntax, provide a structured framework for understanding the system’s functionality. Gherkin uses a Given-When-Then format to define preconditions, actions, and expected outcomes, ensuring scenarios are clear and accessible to all team members.
BDD scenarios serve as both documentation and a foundation for automated testing. By making requirements understandable to all stakeholders, BDD fosters a shared understanding of project goals. This approach reduces misunderstandings and helps ensure that the development effort delivers software aligned with both technical and business needs.
BDD is not merely a testing methodology; it is a communication framework that aligns teams around a common objective. By focusing on system behavior rather than implementation details, BDD prioritizes the user’s perspective, which ultimately leads to software that is robust, reliable, and aligned with business goals.
Behavior-driven development methodology is based on several guiding principles that ensure its effectiveness. The first principle is collaboration across roles. BDD emphasizes the active participation of developers, testers, and business stakeholders in defining system behavior. This collaboration fosters a shared sense of ownership and ensures that technical implementation aligns with business objectives from the outset.
Another key principle is clarity. Behavior-driven Development scenarios are written in plain, natural language using structured formats like Gherkin, making them accessible to all team members regardless of technical expertise. This accessibility bridges the gap between business and technical stakeholders, ensuring everyone understands what the system is expected to do.
BDD also focuses on example-driven development. Scenarios represent real-world examples of how the system should behave in specific situations. By working with concrete examples, teams can identify edge cases and gaps in understanding early in the development process, leading to more practical and actionable requirements.
Lastly, BDD emphasizes continuous feedback and iteration. By integrating scenarios into automated testing frameworks, teams can validate system behavior continuously throughout the development lifecycle. This approach reduces defects, accelerates feedback, and ensures that development remains aligned with business goals as requirements evolve.
Behavior-Driven Development offers numerous benefits that enhance the quality of software development and testing. One of the most significant advantages is improved collaboration. By involving all stakeholders in the definition of requirements, BDD ensures a shared understanding of goals, minimizing miscommunication and aligning technical implementation with business objectives.
BDD also ensures better alignment with user and business needs. Scenarios, grounded in real-world behaviors and user stories, focus development efforts on delivering features that provide tangible value. This reduces the risk of creating unnecessary or misaligned functionality and helps prioritize tasks that align with user expectations.
Another benefit is enhanced test coverage. BDD scenarios, written as concrete examples, naturally cover edge cases and potential issues, leading to more thorough testing and fewer defects. The Given-When-Then format ensures that tests are clear, easy to maintain, and adaptable as requirements change.
Automated BDD scenarios enable faster feedback loops and early defect detection. By continuously validating system behavior, teams can identify and address issues earlier in the development cycle, reducing the cost and effort required to fix defects later. Additionally, BDD provides living documentation that evolves alongside the software, making it a valuable resource for onboarding new team members, validating compliance, and maintaining systems over time.
Below is a detailed example of a Behavior-driven Development scenario for a loan application workflow in a mobile banking app. The comments included explain the purpose of each step in the scenario.
Feature: Loan application via a mobile banking app
# This feature demonstrates how BDD scenarios are structured using Gherkin syntax.
# These scenarios are written in plain language to foster collaboration
# between technical and non-technical stakeholders and ensure clarity of requirements.
Scenario: Successful loan application and instant disbursement
# This scenario provides a concrete example of expected system behavior
# under specific conditions.
Given the customer logs into the mobile banking app using biometric authentication
# “Given” steps define the initial context or preconditions required for the scenario.
# They describe the state of the system before any actions occur.
And navigates to the “Loans” section
# Multiple “Given” steps provide a complete setup of the scenario’s context.
# Each step focuses on a specific part of the precondition.
And is offered a pre-approved loan based on their profile
# Scenarios focus on behavior, not implementation details.
# This step highlights a system behavior critical to the workflow.
And the customer’s profile includes:
| Attribute | Value |
| Credit Score | Excellent | # Tables in Gherkin represent structured data,
| Debt-to-Income Ratio | Below 30% | # ensuring clarity and readability in scenarios.
| Account Verification | Completed |
| AML Screening Status | Passed |
And the customer has no outstanding delinquencies
# Preconditions ensure the scenario starts with a predictable state,
# helping testers focus on the behavior being validated.
When the customer selects a loan amount within the pre-approved limit
# “When” steps describe the actions taken by the user or the system.
# These steps are the events that trigger system behavior.
And chooses a repayment term of 36 months
And uploads all required documents:
| Document | Status |
| Proof of Income | Verified | # Tables in “When” steps provide a clear structure for user inputs.
| Tax Returns | Verified |
And confirms the loan request by accepting the terms and conditions
# The “When” section captures actions, showing how the system transitions from its initial state.
Then the system performs a real-time automated risk assessment
# “Then” steps specify expected outcomes or observable system behaviors.
# These results must be testable and clearly defined.
And assigns the application a “Low Risk” score
# Outcomes are written in precise terms to ensure they can be validated.
And validates compliance with AML and KYC regulations
And generates a personalized loan agreement with the following details:
| Loan Amount | $50,000 | # Outputs are explicitly defined to ensure clarity.
| Term | 36 months |
| Interest Rate | Based on risk profile |
| Monthly Payment | System-calculated |
When the customer digitally signs the loan agreement
# Additional “When” steps describe further interactions required to complete the workflow.
And the system validates the signed document
# Validation ensures that inputs or states are processed correctly.
Then the system instantly disburses the loan amount into the customer’s primary checking account
# Final outcomes confirm that the system behaves as expected.
And generates a repayment schedule starting 30 days from the disbursement date
And sends the customer a notification via:
| Method | Content |
| Push Notification | “Your loan has been disbursed.” |
| Email | “Loan details and schedule attached.” |
And updates the loan status to “Active”
And displays the loan details in the “My Loans” section of the app
And logs the transaction and compliance results for audit purposes
Behavior-Driven Development (BDD) is a transformative methodology for financial application testing. By aligning teams around shared goals and emphasizing system behavior, BDD fosters collaboration, accelerates feedback, and improves test coverage. For financial institutions aiming to deliver reliable, compliant, and user-focused applications, BDD offers a proven approach. If you’re ready to explore the benefits of BDD or enhance your software development processes, contact us for expert guidance.
