IntelliJ IDEA 2024.1 Help

Code coverage

Code coverage in IntelliJ IDEA lets you analyze which lines of code were executed during a particular run. It helps determine the share of code covered by tests and identify areas that lack sufficient test coverage.

Enable the Code Coverage for Java plugin

This functionality relies on the Code Coverage for Java plugin, which is bundled and enabled in IntelliJ IDEA by default. If the relevant features aren't available, make sure that you didn't disable the plugin.

  1. Press Ctrl+Alt+S to open settings and then select Plugins.

  2. Open the Installed tab, find the Code Coverage for Java plugin, and select the checkbox next to the plugin name.

Run with coverage

The entry points for running coverage analysis are the same as you would normally use to run an application:

  • For main method definitions, click Run in the editor gutter, then select Run with Coverage

    A popup appears on clicking the gutter Run icon
  • For run configurations, click More Actions in the Run widget, then select Run with Coverage

    A menu appears on clicking More Actions in the Run widget
  • For Gradle tasks, go to Gradle tool window, right-click the task, and select Run with Coverage

    A menu appears on clicking a task in Gradle tool window

Coverage analysis executes the corresponding run configuration with the coverage agent attached. This agent instruments the bytecode to keep track of the execution line-by-line. After the execution completes, the results of the analysis appear in the IDE.

Coverage suites

The collection of coverage data for a specific run is called a coverage suite.

IntelliJ IDEA can display the results for one or more coverage suites at once. If multiple suites are selected, the IDE displays merged results from these suites. This means that a line is considered covered if it was executed in at least one of the selected suites.

The corresponding suite files are located in the IntelliJ IDEA's system directory:

%LOCALAPPDATA%\JetBrains\IntelliJIdea2024.1\coverage

~/.cache/JetBrains/IntelliJIdea2024.1/coverage

~/Library/Caches/JetBrains/IntelliJIdea2024.1/coverage

Manage suites

  1. In the main menu, go to Run | Manage Coverage Reports Ctrl+Alt+F6.

  2. In the Choose Coverage Suite to Display menu:

    • Use the checkboxes to select active suites. Active suites define the coverage data that is currently displayed in the IDE.

    • Use the Add button Add to import external suite file, for example, generated in the CI server or sent to you by someone else. You can use .ic (IntelliJ IDEA runner) and .exec (JaCoCo runner) files.

      To view an imported suite collected with IntelliJ IDEA runner, you do not have to compile or run the project.

    • Use the Remove button Remove to remove a suite from the list but keep the file in the storage.

    • Use the Delete button Delete to remove a suite from the list and delete the file from the storage.

Read coverage data

IntelliJ IDEA shows coverage results in:

  • Coverage tool window

  • Project tool window

  • Editor

Code coverage results are displayed in the Coverage tool window, in the Project tool window, and in the editor after you launch at least one run configuration with coverage.

Project tool window

The Project tool window displays:

  • the percentage of the covered classes and lines for directories

  • the percentage of the covered methods and lines for classes

Code coverage results in the Project tool window

Coverage tool window

The report breaks down the project by coverage percentage of classes, methods, lines, and branches.

Branch coverage shows the percentage of the executed branches in statements like if-else or switch. It is available for the JaCoCo runner and for the IntelliJ IDEA runner with the Branch Coverage option enabled.

Coverage results in the Coverage tool window

The Coverage tool window has the following options:

Item

Description

the Flatten Packages button

Select whether to show packages hierarchically or flatten the structure to show all of them on the same level.

the Navigate with Single Click button

If this option is on, IntelliJ IDEA automatically opens the selected item in the editor. Otherwise, you need to double-click items to open them.

the Always Select Opened Element button

If this option is on, IntelliJ IDEA automatically locates in the tool window the files that you open in the editor.

the Generate report button

Generate a code coverage report and save it to the specified directory. For more information, refer to Generate coverage report.

the Import External Coverage Report button

Import a coverage suite from disk.

Filters

Filter coverage results. You can choose to view only the classes with uncommitted changes to focus on recent updates or hide the classes that are fully covered with tests.

Editor

In the editor gutter, lines are highlighted according to their coverage status:

  • Full code coverage Green – lines that have been executed

  • Full code coverage Red – lines that have not been executed

  • Full code coverage Yellow – lines that were executed partially, like when only one branch of an if-else statement is visited

To view statistics for a line of code, click the corresponding color indicator in the gutter. A popup that opens shows the number of hits and condition evaluation statistics (only for IntelliJ IDEA runner).

Coverage statistics shown in the editor

Additionally, the statistics popup has the following options:

the Show Tests Covering Line

For JUnit tests: open the test that covers a line in a separate dialog. To be able to use this feature, make sure you ran coverage analysis with the Branch Coverage and Track per test coverage options

the Show Bytecode button

Open the bytecode of the current class in a separate dialog

the Edit Coverage Colors button

Change the colors of the coverage indicators in the gutter

Hide coverage data

Do one of the following:

  • Close the tab with coverage statistics in the Coverage tool window (View | Tool Windows | Coverage).

  • Click coverage highlighting in the gutter and select Hide coverage.

Generate coverage report

  1. Go to Run | Generate Coverage Report, or click the Generate Coverage Report button in the Coverage tool window.

  2. In the Generate Coverage Report dialog, specify the directory to store the generated report and optionally select the Open generated HTML in browser checkbox.

Configure code coverage

In IntelliJ IDEA, there are coverage settings that apply to individual run configurations, and those applicable per-project.

Run configuration settings

For each run configuration, you can specify the scope of the coverage analysis.

Configure classes and packages

  1. Go to Run | Edit Configurations and click the run configuration on the left panel.

  2. Click Modify options, then select the following options under Code Coverage:

    • Specify classes and packages: select this option to configure classes and packages for which you want to see the coverage information.

    • Exclude classes and packages: select this option to configure classes and packages that you want to exclude from coverage.

Project settings

For projects, you can configure the following options:

Show options before applying coverage to the editor

Ask whether to make the recently collected coverage suite active every time you run coverage analysis. In this case a dialog will appear, where you can choose to only display the new results, to add them to the existing results, or save them to storage without viewing.

Do not apply collected coverage

Only save the recently collected coverage suite to storage after you have run coverage analysis. In this case, new coverage data will not be shown unless you explicitly select the corresponding suite in Run | Manage Coverage Reports.

Replace active suites with the new one

Hide the currently shown coverage suites and use the newly collected one after you have run coverage analysis. In this case, only the results from the most recent coverage run will be shown.

Add to the active suites

Add the newly collected coverage suite to the list of active suites after you have run coverage analysis. This keeps the existing coverage results and adds the new results on top of it.

Activate Coverage View

Open the Coverage tool window every time you run coverage analysis.

Choose coverage runner

Select the coverage runner: IntelliJ IDEA or JaCoCo

Branch coverage

only for IntelliJ IDEA runner

Collect granular coverage data for if and switch statements' branches.

Track per test coverage

only for IntelliJ IDEA runner

Lets you trace back to specific tests, during which a line was executed. To navigate to these tests, click the coverage highlighting in the editor gutter, then click the Show Tests Covering Line Show Tests Covering Line.

Collect coverage in test folders

only for IntelliJ IDEA runner

Collect code coverage statistics for tests. By default, coverage data only shows which lines were covered in source roots. Use this option to enable coverage collection in test roots as well.

Ignore implicitly declared default constructors

only for IntelliJ IDEA runner

Exclude the implicit default constructors from coverage statistics. No-arg constructors that are declared explicitly will remain included.

Exclude annotations

only for IntelliJ IDEA runner

Exclude elements marked with the specified annotations from coverage results, for example, Lombok's @Generated elements.

Change colors of the coverage highlighting

  1. Press Ctrl+Alt+S to open settings and then select Editor | Color Scheme | General.

  2. In the list of components, expand the Line Coverage node and select a type of coverage: for example, Full, Partial or Uncovered.

  3. Click the Foreground field to open the Select Color dialog.

  4. Select a color, apply the changes, and close the dialog.

Configure code coverage colors
Last modified: 22 May 2024