TestNG groups

  

What are Testng Groups?

In Testng, groups are used to categorize your test methods logically so you can run:

• A specific set of tests (like "smoke", "regression", "sanity")

• Multiple tests together, even if they are in different classes

Groups allow modular test execution, making large test suites more manageable and efficient.

TestNG Groups revolves around the concept of categorization and selective execution of test methods. They provide a flexible mechanism to label, filter, and run subsets of your total test suite based on defined criteria, without altering the structure of your test classes.The theory of TestNG Groups revolves around the concept of categorization and selective execution of test methods. They provide a flexible mechanism to label, filter, and run subsets of your total test suite based on defined criteria, without altering the structure of your test classes.

1. Categorization and Tagging Theory

At its core, a TestNG Group acts as a label or tag that can be applied to individual test methods, or even entire classes.

• The Goal: To logically organize a large, heterogeneous set of tests into manageable categories.
• The Mechanism: A test method is simply assigned one or more group names (e.g., "Smoke," "Regression," "Database," "UI"). A single test can belong to multiple groups.
• Benefit: This creates a many-to-many relationship where tests are tagged based on their function, scope, or execution time.

2. Selective Execution Theory 

The primary utility of groups is to control which tests are executed during a specific test run. This control is managed through the testng.xml configuration file.

• Inclusion: You can theoretically instruct the TestNG runner to include specific groups. For example, by specifying the "Sanity" group, the runner will only execute methods and classes tagged with "Sanity," skipping all others. This is essential for quickly verifying critical functionality.
• Exclusion: You can also instruct the runner to exclude certain groups. For instance, you might run a full regression suite but explicitly exclude the "LongRunning" group to save time, or exclude the "Database" group if the database is temporarily unavailable.

3. Execution Scope and Filtering

Groups allow for granular filtering at different levels of the TestNG hierarchy.

• Method Filtering: The most common use is to tag and filter individual test methods.
• Class/Package Filtering: A group can be applied at the class or package level, meaning every test method inside that container automatically inherits that group tag. This simplifies organization when dealing with large modules.
• Pre-defined Execution: By combining inclusion and exclusion rules in the testng.xml, a single test class file can support multiple, pre-defined test runs (e.g., a "CI-Build" run that uses the "Smoke" group, and a "Nightly" run that uses the "Regression" group).

Why Use Groups?

• Run a subset of tests without running the entire suite
• Reuse the same test in multiple groupings
• Organize tests based on functionality, feature, or type (example: @smoke, @regression, @login)

Example: TestNG Groups using Java

Step 1: Create Java Test Class with Groups

Below in Test class, we have created Tests which are annotated with @Test and created groups with groups attribute.(ex: groups = {"smoke, "login"}

We can name multiple groups in groups attribute separated with comma. 

import org.testng.annotations.Test;

public class GroupTestExample {

    @Test(groups = {"smoke", "login"})
    public void loginTest() {
        System.out.println("Smoke/Login Test: Login functionality");
    }

    @Test(groups = {"regression"})
    public void profileTest() {
        System.out.println("Regression Test: Profile page validation");
    }

    @Test(groups = {"sanity", "checkout"})
    public void paymentTest() {
        System.out.println("Sanity/Checkout Test: Payment flow");
    }

    @Test
    public void generalTest() {
        System.out.println("General Test: No group assigned");
    }
}

Step 2: Define Groups in testng.xml




Below is the testng.xml file, here only smoke group is included as shown below so tests which is in smoke group will be executed. In above java class only one test is there which has smoke group, so only that test will execute.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd">
<suite name="GroupSuite">
  <test name="SmokeGroupOnly">
    <groups>
      <run>
        <include name="smoke"/>
      </run>
    </groups>
    <classes>
      <class name="GroupTestExample"/>
    </classes>
  </test>
</suite>

Output

Smoke/Login Test: Login functionality

We can also run multiple groups:

<include name="smoke"/>
<include name="sanity"/>

We can also exclude specific groups:

<groups>
  <run>
    <exclude name="regression"/>
  </run>
</groups>

If a test case execution depends upon successful execution of group of test cases then we can also create dependencies on test cases by using 'dependsOnGroups' attribute in @Test annotation, as shown below in code snippet.

@Test(groups = "db")
public void connectToDB() {
    System.out.println("Connected to DB");
}

@Test(groups = "sanity", dependsOnGroups = "db")
public void fetchUserData() {
    System.out.println("Fetched user data after DB connection");
}

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