Summary

The Software System Test Plan defines your systematic approach to verifying that your medical device software meets all specified requirements through comprehensive testing. This document establishes test procedures, acceptance criteria, and documentation standards that ensure your software functions safely and effectively before release.

Why is Software System Test Planning important?

Software system test planning is essential because software defects in medical devices can directly impact patient safety and device effectiveness. Unlike hardware failures that are often immediately apparent, software failures can be subtle, intermittent, or context-dependent, making systematic testing crucial for identifying potential issues before market release. The planning phase ensures you have comprehensive test coverage of all software requirements, establishes objective pass/fail criteria, and creates documentation that demonstrates regulatory compliance. Without proper test planning, you risk missing critical software defects, failing to demonstrate requirement compliance, or lacking sufficient evidence for regulatory submissions.

Regulatory Context

Under 21 CFR Part 820.30(g) (Design Validation) and FDA Guidance “General Principles of Software Validation”:
  • Software testing must demonstrate that software requirements are correctly implemented
  • Testing must cover normal operation, boundary conditions, and error conditions
  • IEC 62304 compliance required for medical device software lifecycle processes
  • Cybersecurity testing per FDA premarket cybersecurity guidance for networked devices
Special attention required for:
  • Software of Unknown Provenance (SOUP) verification and risk assessment
  • Cybersecurity testing for devices with network connectivity
  • Software change control and regression testing procedures
  • Integration testing between software and hardware components

Guide

Understanding Software System Testing Scope

Software system testing verifies that your complete software system meets all specified requirements when operating as an integrated whole. This differs from unit testing (individual components) and integration testing (component interactions) by focusing on end-to-end system behavior under realistic operating conditions. Your test plan must address functional requirements (what the software does), performance requirements (how well it performs), safety requirements (how it handles errors and failures), and usability requirements (how users interact with it).

Developing Test Cases from Requirements

Each software requirement must be traceable to specific test cases that verify the requirement is correctly implemented. Start with your system requirements and subsystem requirements to identify what needs testing. Functional test cases verify that software features work as specified. For each functional requirement, create test cases that exercise normal operation, boundary conditions, and error conditions. Include both positive testing (verifying correct behavior) and negative testing (verifying proper error handling). Performance test cases verify that software meets timing, throughput, and resource utilization requirements. Test under various load conditions, including peak usage scenarios and resource-constrained environments. Safety test cases verify that software handles failures gracefully and maintains safety even when components fail. Test error detection, error recovery, and fail-safe behaviors identified in your risk analysis.

Establishing Test Environments and Data

Your test plan must specify test environments that represent realistic operating conditions. Consider different hardware configurations, operating system versions, network conditions, and user environments your software will encounter. Test data management is crucial for reproducible testing. Plan for test data that covers normal use cases, edge cases, and error conditions. For medical device software, ensure test data doesn’t contain real patient information and consider using synthetic data that represents realistic clinical scenarios. Configuration management ensures test environments remain stable and controlled. Document software versions, hardware configurations, and environmental conditions for each test execution.

Defining Acceptance Criteria

Each test case requires objective, measurable acceptance criteria that clearly define pass/fail conditions. Avoid subjective criteria that could lead to interpretation disputes. Functional acceptance criteria should specify expected outputs, behaviors, or state changes for given inputs. Include timing requirements where relevant (e.g., “response time <2 seconds”). Performance acceptance criteria should specify measurable thresholds for response times, throughput, resource usage, and availability. Base these on your system requirements and user needs. Safety acceptance criteria should verify that safety mechanisms function correctly and that the software fails safely when errors occur.

Planning Test Execution and Documentation

Your test plan must specify who executes tests, when tests are executed, and how results are documented. Consider whether tests will be manual, automated, or a combination of both. Test execution sequencing should consider dependencies between tests and optimize for efficient execution. Some tests may require specific system states or data conditions established by previous tests. Results documentation must capture sufficient detail to demonstrate requirement compliance and support regulatory submissions. Plan for documenting test procedures, actual results, pass/fail determinations, and any deviations or anomalies.

Handling Test Failures and Anomalies

Your test plan must address how test failures are handled. Not all test failures indicate software defects - some may result from test environment issues, incorrect test procedures, or requirement ambiguities. Failure investigation procedures should determine root causes and appropriate corrective actions. Document whether failures result from software defects, test issues, or requirement clarifications. Regression testing ensures that defect fixes don’t introduce new problems. Plan for retesting affected functionality and related areas that might be impacted by changes.

Example

Scenario: You are developing a diabetes management app that tracks blood glucose readings, calculates insulin dosing recommendations, and provides trend analysis. The app integrates with glucose meters via Bluetooth and stores data in a cloud database. Your software system test plan covers functional testing of glucose data import, insulin calculation algorithms, and trend analysis features. Performance testing verifies app responsiveness and data synchronization times. Safety testing ensures the app handles invalid glucose readings appropriately and provides appropriate warnings for extreme values. Integration testing verifies proper communication with glucose meters and cloud services.

Software System Test Plan

Document ID: SSTP-001
Version: 1.0

1. Purpose

This document defines the system testing approach for the DiabetesManager mobile application to verify all software requirements are correctly implemented and the system operates safely and effectively.

2. Scope

This test plan covers the complete DiabetesManager system including mobile application, cloud services, device integration, and user interfaces.

3. Test Strategy

3.1 Functional Testing
  • Glucose Data Management: Verify data entry, validation, storage, and retrieval
  • Insulin Calculation: Test dosing algorithms against clinical scenarios
  • Trend Analysis: Validate statistical calculations and graphical displays
  • Device Integration: Test Bluetooth connectivity and data synchronization
3.2 Performance Testing
  • Response Time: Verify app responsiveness <2 seconds for all user actions
  • Data Synchronization: Test cloud sync performance under various network conditions
  • Battery Usage: Validate power consumption within acceptable limits
3.3 Safety Testing
  • Input Validation: Test handling of invalid glucose readings and user inputs
  • Error Handling: Verify appropriate warnings for extreme glucose values
  • Fail-Safe Behavior: Test app behavior when cloud services are unavailable

4. Test Cases

Test IDRequirementTest DescriptionAcceptance Criteria
TC-001REQ-001Manual glucose entry validationApp accepts valid glucose values (20-600 mg/dL), rejects invalid values with clear error message
TC-002REQ-005Insulin calculation accuracyCalculated insulin dose within ±5% of expected value for standard clinical scenarios
TC-003REQ-012Bluetooth device pairingApp successfully pairs with supported glucose meters within 30 seconds
TC-004REQ-018Extreme value warningsApp displays appropriate warnings for glucose <70 or >300 mg/dL

5. Test Environment

  • Mobile Devices: iOS 14+ (iPhone 8 and newer), Android 9+ (Samsung Galaxy S9 and newer)
  • Network Conditions: WiFi, 4G LTE, limited connectivity scenarios
  • Test Glucose Meters: Accu-Chek Guide, OneTouch Verio models
  • Test Data: Synthetic glucose datasets covering normal, hypoglycemic, and hyperglycemic ranges

6. Test Execution

  • Phase 1: Functional testing on primary test devices
  • Phase 2: Performance testing under various load conditions
  • Phase 3: Safety and error handling testing
  • Phase 4: Integration testing with external devices and services

7. Pass/Fail Criteria

  • Pass: All test cases meet acceptance criteria, no critical defects remain unresolved
  • Fail: Any critical safety requirement fails, >5% of test cases fail, or performance requirements not met

Q&A