Greenhouse of JUnit automated tests

Greenhouse of Test Automation: Part IV

How to store JUnit tests in an InfluxDB

Instead of looking at bad memes, wouldn’t you rather extract data of JUnit tests and store them in an InfluxDB? Visualizing those tests on a Grafana dashboard to build trust in test automation and analyze the results ? Or are you looking for inspiration to create your own solution? In all cases you are in the right place!

Created my own bad meme at img-flip.com

🌱 Welcome to the blog series about visualizing test automation. Dutch greenhouses excel in sustainability and serve as a main thread running through this journey. I wrote about the concept of extracting test results, storing them in an InfluxDB, and how this works for TestCafé tests. Now it’s time to deep dive in the implementation for JUnit tests, to enable visualization on a Grafana dashboard!

How to extract and store JUnit tests in an InfluxDB?

I didn’t find an out the box solution to help me answer this question, so I made my own; junit-listener-influxdb. Use it in a project with JUnit tests to extract and store them in an InfluxDB. It’s ALMOST plug & play:

• 🔌 Plug
  - Import the junit-reporter-influxdb as a dependency
• 🔧 Configure
  - Set the right environment variables
• 🎮 Play
  - Run your Influx database on the specified host and port
  - Run your JUnit tests

That’s it! Note that the junit-listener-influxdb library is generically set up where the tests run remotely via Gitlab pipelines. You might want to save data of your tests specific to your context. My advice? Check out the details and possibilities in this README. Then fork the library and specify it to save the most relevant data for your project, like test types, categories, or application names. I will give an example why and how to customize test categories.

Customize JUnit test extraction

When visualizing tests on a dashboard, it is very useful to group them based on categories, risk or feature for example. This is enabled by storing tags with the tests. Create tags with fixed values in the junit-listener-influxdb library like the example below shows.

Specify the tags you want to filter your JUnit tests on

Add the relevant categories to yourJUnit test (note the difference between Java & Kotlin). These tags will be saved along the tests, to enable filtering during the setup of a Grafana dashboard.

Java:

@Tag(TestMetadata.Risk.HIGH)
@Tag(TestMetadata.Feature.LOGIN)

Kotlin:

@Tags(
        Tag(TestMetadata.Risk.HIGH),
        Tag(TestMetadata.Feature.LOGIN)
)

How does the junit-reporter-influxdb library work?

The picture below shows the concept of extracting and storing test results in an InfluxDB. With every step I will explain the implementation for the junit-reporter-influxdb library below.

Visualization of the JUnit test automation sensor: junit-reporter-influxdb

Extract JUnit test data

My environment is enriched with different flavors of backend tests. The tests are written both inJava and Kotlin, and there is a distinction of three different test layers:

1. Unit : test in isolation using the Mockito, JPA or WebMVC extension.
2. Component : test within Spring application context using the SpringBootTest extension, external services are mocked using WireMock.
3. Integration : in theSpring application context the integration between the system under test and external services is tested.

Luckily they have one thing in common; the tests run using the JUnit testrunner. The JUnit TestExecutionListener provides an interface to tap into the tests during a test run, and supports all above mentioned extension flavors. Only condition is that the tests must run using JUnit5. Upgrading from JUnit4 to JUnit5 can be a challenge for old services running with ancient Spring versions, I can tell 😵.

The methods of TestExecutionListener are called during the test run; at the beginning and end of a test, class or complete test run. junit-listener-influxdb contains the implementation of those methods, and a service loader to enable the use of the library by other services.

Store JUnit test data in an InfluxDB

Let’s zoom in the executionFinished method of the TestExecutionListener, which is called when a JUnit test is completed. I use the influxdb-java client to interact with InfluxDB in a Java environment. This client helps to formulate, address and send the data to an InfluxDB.

Structure JUnit test data in an envelope which fits perfectly in an InfluxDB

• ✉️ Formulate; set the data in the correct structure
  The completed test is accessible via the input parameters of executionFinished. Relevant data like duration of the test are processed and structured in the plain old Java object (POJO) TestResult . Annotations provided by influxdb-java ensure that the test result fits perfectly in the Influx table testResults (@Measurement). The POJO is saved as a Point, which is a single data record in Influx terminology.
  All test results are collected in a batch of Points; we only want to connect with the database and send all results at once, when the test run is done. Finally, I reset the test result to extract the next one with a clean slate.

Put the right address of the Influx database on the envelope

• 📧 Address; set the properties for the correct database
  When the junit-listener-influxdb starts, an InfluxDB object is created with the correct address of the Influx database we want to send the data to. These are originated from the environment variables. You can set them locally when running the application, or as remote variables in your pipeline.

Send the envelope with JUnit test data to the Influx database!

• 📩 Send; post the data to the database
  When the test run is completed, a connection with the addressed Influx database is setup and checked. All test results collected in the batch of Points are validated and send with a REST POST call, provided by the InfluxDB client. Afterwards, the connection with the database is closed.

That’s it! To me it was quite a puzzle to find out how the data of JUnit tests can be extracted and processed. Several moments I wanted to throw my laptop through the window, but with help from my colleagues of deTesters and some perseverance I struggled through. I learned a lot and can monitor JUnit tests on a Grafana dashboard now!

What’s next? How to display this testdata in an Grafana dashboard, and the key question of this project; how is it used in practice and what is the result? Stay tuned!

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