Get started - Cover Pipeline

This topic details how to use Diffblue Cover to write tests for your project as part of a CI pipeline. It outlines the basic commands that you will need to add to your CI scripts, and provides general information to understand the key steps - for specific CI tools, refer to the following:


This topic assumes that you have:

  • A basic understanding of Cover CLI - see Get started - Cover CLI.

  • A Maven or Gradle project that:

    • Compiles.

    • Does not have non-compiling or failing tests.

    • Is stored in a Git repository with a CI tool enabled.

  • A basic understanding of your chosen CI tool.

  • The ability to store secrets variables for your CI tool.

  • Diffblue Cover CLI release zip stored in the cloud, along with an appropriate license key.


To integrate Diffblue Cover into your CI pipeline, we will guide you through creating a CI script that:

1. Building the project

To run Diffblue Cover CLI your project must be built. Running the project’s tests is not required, and you will save time by skipping them, but they do need to compile and pass. For example, you can use the following command to build a Maven project while skipping the tests:

mvn --batch-mode --no-transfer-progress clean install -DskipTests

2. Downloading and activating Diffblue Cover CLI

You need to give the CI run access to the Diffblue Cover files and activate the dcover license in order to write tests.

This step assumes that you have a URL with the Diffblue Cover CLI release zip and the license key for online activation during the CI run. If your license allows it you may wish to install Diffblue Cover with offline activation. See Licensing.

You will need to add two secret variables which, here, will be represented as environment variables:

  • The first secret variable with the name DIFFBLUE_COVER_URL and the value set to the URL of the Diffblue Cover CLI release zip file.

  • The second with the name DIFFBLUE_COVER_LICENSE_KEY and the value set to your Diffblue Cover license key.

Append the code for getting, unzipping, and activating dcover, to your script.

  mkdir -p "~/dcover"
  cd "~/dcover"
  curl --silent --show-error --location --output "" "$DIFFBLUE_COVER_URL"
  unzip -q ""
  rm -f ""
  dcover activate "$DIFFBLUE_COVER_LICENSE_KEY"

This will put the Diffblue Cover files into the dcover directory in the root of the workspace. The files contain a script called dcover which has the relative path dcover/dcover (or dcover\dcover.bat in Windows environments). The script is added to your PATH variable so that you can invoke Diffblue Cover CLI as dcover (or dcover.bat).

Push the changes so that your CI is triggered - ensure that you can see the successful activation of dcover in your CI output before moving on. You will see a line starting with "Successfully activated key" if this was successful. If Diffblue Cover did not successfully activate, please see Licensing or contact Diffblue Support.

3. Running Diffblue Cover CLI to create tests

Now that Diffblue Cover is running in CI, you can use it to write tests. The next two items show how to write tests for a single module, and then how to extend this to all modules.

Creating tests for a single module:

Choose a module to test in your project. Append the following to your workflow file, changing moduleToTest to a module in your project or, if your project does not have modules, --working-directory moduleToTest can be removed or changed to --working-directory. Note that the --batch option makes the output more suitable for CI, as it ensures the CI logs are not cluttered with progress bar output.

  dcover create --working-directory="moduleToTest" --batch

Push the changes so that dcover runs in the CI. Once successfully complete, you should expect to see output that looks like this:

INFO  Found 7 callable methods in 2 classes
INFO  Creating tests:
INFO  ---------------
INFO  All 5 created tests were successfully validated.

If you don't see this output, the dcover command may need a small modification for your project, or dependencies adding, until it works. The output gives you warnings along the way to guide you. See Commands & Arguments for more information.

Depending on the size of your module/project, creating tests could take a while. You may wish to restrict test creation to a single class by specifying its fully qualified name:

  dcover create com.somepackage.SomeClass --working-directory="moduleToTest" --batch

Creating tests for all modules:

To write tests for all the modules, you can use a loop as follows:

  for MODULE in module_name_1 module_name_2 module_name_3
    dcover create --batch --working-directory="$MODULE"

4. Committing the created tests to a branch

To see the new tests created in the previous step in your project, you need to commit them and push back to the repository. Depending on your CI tool you may also need to configure a Git user to create the commit. We recommend creating a service account for this.

  git config db-ci-bot
  git config

To commit the tests, append the following to your script. This will check for any changes to Diffblue tests, add them to a commit and push to your branch.

  if [ -n "$(git status --short **/*" ]; then 
    git add **/*
    git commit --message "Update Unit Tests for $(git rev-parse --short HEAD)"
    git push --set-upstream origin
    echo "Nothing to commit"

Note: Be careful not to create an infinite CI loop here. We recommend checking the author of each commit to ensure you're not creating tests for a commit authored by your Diffblue service account.

LAST_NON_BOT_COMMIT="$(git rev-list -1 --author='^(?!db-ci-bot).*$' --perl-regexp HEAD --no-merges)"
LAST_COMMIT="$(git rev-list HEAD -1 --no-merges)"

Next steps

In this topic we've outlined the basic commands that you will need to add to your CI scripts, but we've only provided general information to understand the key steps - for specific CI tools, refer to the following:

Diffblue Cover - one AI

Diffblue Cover is also provided as an IDE plugin tool so you can write tests with one click in the IntelliJ IDE (see Get started - Cover Plugin) and as a developer CLI tool to write tests for your entire project, all in one hit (see Get started - Cover CLI).

But Cover CLI, Cover Plugin, and Cover Pipeline are not mutually exclusive, in fact they make perfect partners. Use Cover Plugin within the IntelliJ IDE to write and check unit tests for your application during development, and also use Cover CLI directly from the IntelliJ Console or your OS command line to access the wider and deeper functionality provided by Cover CLI - finally, use Cover Pipeline within your CI tool to automate the whole process and provide consistency across your organization.

Last updated