Visualizations in Cover Reports

This describes the various visualizations in Diffblue Cover Reports.
Cover Reports has many visualizations that simplify analysis of coverage data generated by the dcover CLI. Each visualization is described in detail.


The heat map shows coverage for the whole project, divided into sections of the appropriate size and color:
Use the toggle switches above the map to:
  • Turn the colors on/off (the rectangles will recolor).
  • Show the total lines of code (the rectangles will resize).
  • Show the uncovered lines of code (the rectangles will resize).
Hover over the rectangles to see the name and coverage details. This is especially useful if some of the rectangles are smaller.


The visualizations shown are very similar for both Cover CLI and Cover Plugin:
Total unique users per day:
Total number of write test operations per day:
Total tests produced per day:

Coverage Over Time

These charts compare coverage over time for a class, package or a module, on the same branch. The example below shows a run coverage over time:
All runs are shown as points on the graph and the latest run is highlighted - hover over a run point to display details.

Coverage Sources

Coverage sources are represented by a pie chart and a table. The pie chart is, by default, split into eight sections - each represents how the code is covered by tests:
  • By manual tests only - percentage of code covered exclusively by Manual Tests only (existing developer written tests).
  • By Diffblue tests only - percentage of code covered by exclusively by Diffblue Cover Tests only.
  • By Diffblue and manual tests - percentage of code covered by Diffblue Cover Tests and Manual Tests (existing developer written tests) - i.e. this is the overlap of the two types of test.
  • Not tested, Untestable, Trivial, Unknown - percentage of code that Diffblue Cover was unable to write tests for. In many cases this is due to issues such as private methods, empty methods, trivial setters and getters, etc. You can use the Coverage Detail tab to get more detailed information (output codes).
  • Excluded - percentage of code that was excluded from test creation.
The percentage displayed on the section of the pie chart represents the lines of code covered by that test source as a percentage of overall lines in the module. You can hover over any section to get the information of each section. The raw amount of lines covered by that test source is displayed in the table. Here is an example of the Coverage sources pie chart where the "Not tested" section is hovered over: