06 June, 2016

Working with @TestInstance annotation

Sometimes one would need to gain access to the test class instance to which an @Test annotated test method belongs to, from within a data provider. This could be particularly useful in cases, wherein the data provider may need to behave differently based on the type of the class to which the @Test method belongs to.

This is where the @TestInstance annotation from TestNG comes into picture. This annotation is typically used on the parameter of a data provider method.

Here’s a sample data provider.

public static class LocalDataProvider {
    @DataProvider (name="data-provider")
    public static Object[][] getData(@TestInstance Object object) {
        System.err.println("The instance passed in was " + object.getClass().getCanonicalName());
        return new Object[][] {
            {1},
            {2}
        };
    }
}

Here are two test classes that make use of the above cited data provider.

First test class

public static class FirstTestClass {
    @Test (dataProvider="data-provider", dataProviderClass=LocalDataProvider.class)
    public void testmethod(int number) {
        System.err.println("Value = " + number);
    }
}

Second test class

public static class SecondTestClass {
    @Test (dataProvider = "data-provider", dataProviderClass=LocalDataProvider.class)
    public void testmethod(int number) {
        System.err.println("Value = " + number);
    }
}

Now when you run both the above mentioned test classes, you should see an output as below :

[TestNG] Running:
  /Users/krmahadevan/Library/Caches/IntelliJIdea2016.1/temp-testng-customsuite.xml
The instance passed in was organized.chaos.TestClassContainer.FirstTestClass
Value = 1
Value = 2
 
The instance passed in was organized.chaos.TestClassContainer.SecondTestClass
Value = 1
Value = 2
 
===============================================
Default Suite
Total tests run: 4, Failures: 0, Skips: 0
===============================================

For any queries, log an issue here.

Tags: TestNG

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Krishnan Mahadevan

Working with @TestInstance annotation

Working with @TestInstance annotation