Purpose

Unit Test Coverage shows a percentage of a source code covered by unit tests. It is a mix of Line coverage and Condition coverage. The metric can be also calculated for a new code only.

How this metric helps

Unit Test Coverage may be a guide for indicating a lack of coverage via Automated Testing - just because Unit Testing is the essential part of the Testing Pyramid. A trend helps to understand how a coverage is changing over time, if it is actually growing or falling and how those trends correlate with plans/investments about appropriate development efforts related to Unit Tests. Lack of coverage is typically a key obstacle for implementing the Continuous Integration and Continuous Delivery  (CI/CD) on a project.

How it works

Chart overview

Chart shows Unit Tests Coverage in % by month:

In case if multiple Sonar projects are configured for a project in PERF, there is an option to view a summary over all them:

Calculation formula

Unit Test Coverage = (CT + CF + LC) / (2*B + EL),

where

• CT = conditions that have been evaluated to 'true' at least once 
• CF = conditions that have been evaluated to 'false' at least once
• LC = covered lines = lines_to_cover - uncovered_lines
• B = total number of conditions
• EL = total number of executable lines (lines_to_cover)

RAG thresholds: Red <= 20%, Amber <= 50%.

Unit Test Coverage for a New Code, % calculation is Identical to Unit Test Coverage but restricted to new/updated source code.

Data Source

Data for the metric can be collected from Sonar.