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Arvind Choudhary
Arvind Choudhary

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TestNG testing framework — Parameterization

#testing #automationtestin #test #testng

TestNG

What is Parameterization?

Whenever we define any parameters on any of our methods, it means we are parametrizing that method. e.g. assuming areaOfSquare(int side);takes one argument which is integer and returns ares of square. it also allows you to use the same method for N. no of values.

@test method of TestNG supports parameterization, which in simple terms means it allows us to pass values to our test method at runtime.

Ways to Parameterize @test Method

  1. @DataProvider
  2. @Parameters

Parameterization with @DataProvider annotation

Always remember to use below 2 if plan on parameterizing your @test with data provider.

  1. @DataProvider annotation with name attribute.
  2. @test with attribute dataProvider having same value as specified for above step.

Code:

import org.testng.annotations.DataProvider; import org.testng.annotations.Test; public class DataProviderDemo { /** * always use name attribute for your dataProvider(), you can have * N. no of dataprovider in your Test class and with the help of dataprovider attribute of @Test(refer to line 57) * you can specify which dataprovider method to use. */ // always returns 2D Object array @DataProvider(name = "testData") public Object[][] dataProvider(){ // 2D Object array initialized Object[][] objectArray = new Object[2][2]; /** * 2D Array structure * | abc | cde | * | efg | hij | * * what @data provider will do here is that it will send data of one row at a time to test method, * then next row and so on. * * no. of rows = no. of times your @Test will get executed */ // adding value in objectArray objectArray[0][0] = "abc"; objectArray[0][1] = "cde"; objectArray[1][0] = "efg"; objectArray[1][1] = "hij"; // return 2D Object array return objectArray; } /** * make sure to use dataProvider attribute on your @Test annotation(refer to line 57), * * Also change you method signature according to what you are passing from your dataProvider, * if you are not sure on what you should do then you can also keep your parameter type as String & * testng would typecase it for you to string. * * no. of parameters on @test method should be same as no. of Object defined on your object array(column-wise). * ref line 19, we have 2 columns and 2 rows. so you should have 2 parmaters(2 columns) in your method signature. * (ref line no. 58) * -------------------------OR--------------------------- * * use (String... args), here dont have to specify each parameter, * you will get one array which is args and you can work with it with the help of index, * each parameter will be stored on one index * assuming current case your array will have 2 indexes [0 & 1] * where 0th index would hold first value and 1st index would hold second value. * (ref line no. 63) */ @Test(dataProvider = "testData") // line 57 public void testMethod(String val1, String val2){ //line 58 System.out.println("testMethod called with ["+val1+", "+val2+"]"); } @Test(dataProvider = "testData") public void testMethod1(String... args){ //line 63 System.out.println("testMethod1 called with ["+args[0]+", "+args[1]+"]"); } }
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Output:

testMethod called with [abc, cde] testMethod called with [efg, hij] testMethod1 called with [abc, cde] testMethod1 called with [efg, hij]
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Parameterization with @Parameters annotation

Passing value with @Parameters is bit tricky here as we will be passing values from testng.xml

TestNG.xml

 <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd"> <suite name="Suite"> <test name="Test1"> <parameter name="value1" value="abc"></parameter> <parameter name="value2" value="cde"></parameter> <parameter name="value3" value="klm"></parameter> <classes> <class name="ParametersDemo" ></class> </classes> </test> <!-- Test --> <test name="Test2"> <parameter name="value1" value="efg"></parameter> <parameter name="value2" value="hij"></parameter> <classes> <class name="ParametersDemo" ></class> </classes> </test> <!-- Test --> </suite> <!-- Suite -->
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Script

import org.testng.annotations.Optional; import org.testng.annotations.Parameters; import org.testng.annotations.Test; public class ParametersDemo { /** * * in @Parameters you should specify parameter name * and same should be present in testng.xml. * refer to line 5 & 13 of testng.xml * * @param val1 parameter should be specified in test.xml * @param val2 parameter should be specified in test.xml * @param val3 is Optional, if specified well it would take specified value else defualt value * refer to line 15, we have use @Optional */ @Test @Parameters({"value1","value2","value3"}) public void testMethod(String val1,String val2,@Optional("default") String val3){ System.out.println("testMethod called with ["+val1+","+val2+","+val3+"]"); } }
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Output:

testMethod called with [abc,cde,klm] testMethod called with [efg,hij,default]
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As you see above for second test tag we only specified 2 parameters instead of 3 and because of @Optional usage we didn’t get any error.

if you would have not specified @Optional and you didn’t specify parameter in testng.xml you will below error.

testMethod called with [abc,cde,klm] org.testng.TestNGException: Parameter 'value3' is required by @Test on method testMethod but has not been marked @Optional or defined
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Useful URLs:
Javatpoint parameters

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