Merv-Local + JUnit 5 guide

Introduction

JUnit 5 is the industry-standard framework for unit and integration testing in Java applications, offering powerful features such as annotations, assertions, parameterized tests, lifecycle management, and extension support. Merv-Local integrates via @ExtendWith(MervJUnitHandler.class) and automatically capturing test execution details and generating rich, interactive HTML reports. These reports, stored in the directory specified by merv.report.folder.

Add dependency

Add MERV to your project (use the latest version from Maven Central when available):

<dependency>
  <groupId>io.github.techelliiptica</groupId>
  <artifactId>merv-client-api</artifactId>
  <version>4.0.0</version>
</dependency>

Gradle:

testImplementation "io.github.techelliiptica:merv-client-api:4.0.0"

Configure merv.properties

Place merv.properties in your project root (the directory where you run mvn test or ./gradlew test — typically next to pom.xml).

Sample Configuration

merv.local=true
merv.regression_suite=Your Regression Suite Name
merv.report.folder=./merv-reports

Download sample merv.properties

Common properties

Register JUnit 5 extension

Add the extension to each test class, or register it once for the whole module:

import org.junit.jupiter.api.extension.ExtendWith;
import org.teche.merv.client.plugin.MervJUnitHandler;

@ExtendWith(MervJUnitHandler.class)
class MyTests {
  // @Test methods, @BeforeEach, etc.
}

Note: @ExtendWith need to implement at class level not method level.

Global registration (all tests in the module):

# src/test/resources/junit-platform.properties
junit.jupiter.extensions.autodetection.enabled=true

# src/test/resources/META-INF/services/org.junit.jupiter.api.extension.Extension
org.teche.merv.client.plugin.MervJUnitHandler

Or use a base class with @ExtendWith(MervJUnitHandler.class) that your test classes extend.

JUnit maps each @Test method to a Merv testcase. @BeforeEach, the test body, and @AfterEach appear as steps in the suite report.

Bind automation (optional)

When merv.screenshot=true, register your driver or page before steps that should capture screenshots:

import org.teche.merv.client.plugin.AutomationTool;
import org.teche.merv.client.plugin.MervJUnitHandler;

// Selenium
MervJUnitHandler.setAutomationToolObject(AutomationTool.SELENIUM, driver);

// Playwright Java
MervJUnitHandler.setAutomationToolObject(AutomationTool.PLAYWRIGHT, page);

Clear the binding in @AfterEach with setAutomationToolObject(null, null) when using parallel tests.

Plugin steps in tests

Use MervReporter — the same API as Cucumber and TestNG:

import org.teche.merv.client.plugin.MervReporter;

MervReporter.info("Reached checkout page");
MervReporter.testdata("Request body", jsonPayload);
MervReporter.validation("Order total", expectedTotal, actualTotal);

Each call creates a typed step (INFO, TEST_DATA, ASSERTION) in the live and final HTML reports.

File test data

Attach a file as test data — copies into the report folder and renders inline in HTML when possible:

import java.io.File;
import org.teche.merv.client.plugin.MervReporter;

MervReporter.testdata("Payload", new File("src/test/resources/payload.json"));
MervReporter.testdata("Screenshot ref", new File("screenshots/expected.png"));

• Text / JSON / CSV / Java — inline preview in the step
• Images — inline thumbnail; click to zoom
• Other files — download bar (max 20 MB per file)

Step screenshots

When merv.screenshot=true and a driver is bound, Merv captures a PNG after each executed step and stores it under {runFolder}/screenshots/.

In merv-report.html and merv-report-live.html:

• Steps with screenshots show a camera icon on the title
• Click the step header (title + status row) to show or hide the screenshot
• Use the toolbar Show screenshots toggle for the screenshot movie; per-step toggles still work when it is off

Run tests

mvn test

Gradle: ./gradlew test. Merv creates a timestamped run folder and refreshes index.html while tests execute.

Viewing Merv reports

After a run, reports live under {merv.report.folder} (for example ./merv-reports/). Open paths through a local web server — not via file:// in the file manager.

• index.html — dashboard: suite grid, KPI charts, consolidated views
• {runFolder}/html/merv-report.html — final suite report for one run
• {runFolder}/html/merv-report-live.html — live suite view while tests run (polls JSON every 5s)

Open with a web server

Merv-Local reports load JSON and charts with fetch. Browsers often block that on file:// URLs. Use your IDE’s static server (or any local HTTP server) so the address bar shows http://localhost:….

Other editors and CI

Any local static server works: npx serve merv-reports or python3 -m http.server --directory merv-reports, then open http://localhost:…/index.html.

Troubleshooting

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