Test coverage is the degree to which a product, system, or process is verified by tests to ensure that all relevant requirements, functions, and components have been validated.
In the industrial context, especially in the production and validation of hardware, software, or embedded systems, test coverage means measuring how much of the product has been effectively tested — and what was left out.
Well-planned test coverage drastically reduces field failures, rework, and warranty costs, as well as increases confidence in the quality of the delivered product.
🧠 Types of Test Coverage
| Type of Coverage | Example in the industrial test environment |
|---|---|
| Functional | Each function of the product is tested (e.g., digital output turns on with logical signal) |
| Electrical | Verification of all inputs, outputs, voltages, and currents |
| Software / Firmware | Testing of all commands, protocols, responses, updates |
| Communication | Checking protocols: I²C, SPI, CAN, RS-485, Modbus etc. |
| Mechanical / Sensorial | Sensors, buttons, actuators, displays, connectors, LEDs |
| Component Coverage | Have all internal functional blocks of the DUT been exercised? |
📊 How to Measure Coverage?
- Listing of all product requirements with traceability to the tests
- Comparison between what was defined, what was tested, and what was omitted
- Use of coverage matrices, traceability dashboards, automated logs
- Indicators such as % of code lines tested, % of commands exercised, etc.
🔧 How AJOLLY Testing Ensures Effective Test Coverage
AJOLLY Testing applies a technical, systematic, and documented approach to maximize test coverage in its projects, ensuring confidence, traceability, and efficiency.
📐 Coverage Planning from the Start
- Definition of coverage matrix with the client (requirements × tests)
- Cross-review between product engineering, quality engineering and test engineering
- Creation of modular, standardized, and reusable test sequences
🛠️ Technical Implementation of Tests
- Automated functional tests with input and scenario variations
- Validation of communication, failure response, limits, and protocols
- Simulation of critical events, stress tests, response curve
📊 Traceability and Analysis
- Generation of coverage reports by batch, product, series, station
- Integration with MES, database, and dashboards (e.g., Power BI, Grafana)
- Graphical reports with coverage gaps and points of attention
⚠️ What Happens with Low Coverage?
- Undetected failures in production
- Increased rework, returns, and loss of customer trust
- Undiagnosed intermittent issues
- Compromised FPY and OEE statistics
With AJOLLY Testing, test coverage is not just a number, but a commitment to delivering validated, safe, and traceable products.