Selenium Automation Testing using Java: Assertions in TestNG

Assertions:

Types of Assertions:

1.Hard Assertions

2.Soft Assertions

1.Hard Assertions:

if given assert statement fails, it stops program execution there it self, it will not execute any stmts after that and also it fails test method.

Assert is predefined class in TestNg, which has different methods, can be used to assert the given cond is true / false

Methods in "Assert" Class:

1.Assert.assertEquals(actual, expected):

Compares if the actual value is equal to the expected value.

2.Assert.assertNotEquals(actual, expected):

Compares if the actual value is not equal to the expected value.

3.Assert.assertTrue(condition):

Checks if the given condition is true.

4.Assert.assertFalse(condition):

Checks if the given condition is false.

5.Assert.assertNull(object):

Checks if the given object is null.

6.Assert.assertNotNull(object):

Checks if the given object is not null.

ex:

package TestNGAsserionsBasics;

import org.testng.Assert;

import org.testng.annotations.Test;

public class AssertionsBasics

{

@Test

public void testA()

{

System.out.println("test A - stmt-1");

// assert "ram" and "ram" are equal or not

// passed

Assert.assertEquals("ram", "ram");//Pass

// assert "Ram" and "sita" are equal

Assert.assertEquals("ram", "sita");

// false-- Fail this stmt

// assert statement -failed

// if assert statement fails, it stops program execution there itself,

//it wont execute any next stmt,

/// it will fail the test method also

//java.lang.AssertionError: expected [sita] but found [Ram]

System.out.println("test A - stmt-5");

}

o/p:

[RemoteTestNG] detected TestNG version 7.0.0

test A - stmt-1

FAILED: testA

java.lang.AssertionError: expected [sita] but found [Ram]

at org.testng.Assert.fail(Assert.java:97)

at org.testng.Assert.assertEqualsImpl(Assert.java:136)

at org.testng.Assert.assertEquals(Assert.java:118)

at org.testng.Assert.assertEquals(Assert.java:575)

at org.testng.Assert.assertEquals(Assert.java:585)

at TestNGBasics.AssertionsBasics.testA(AssertionsBasics.java:21)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.base/java.lang.reflect.Method.invoke(Method.java:564)

at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:133)

at org.testng.internal.TestInvoker.invokeMethod(TestInvoker.java:584)

at org.testng.internal.TestInvoker.invokeTestMethod(TestInvoker.java:172)

at org.testng.internal.MethodRunner.runInSequence(MethodRunner.java:46)

at org.testng.internal.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:804)

at org.testng.internal.TestInvoker.invokeTestMethods(TestInvoker.java:145)

at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:146)

at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:128)

at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

at org.testng.TestRunner.privateRun(TestRunner.java:770)

at org.testng.TestRunner.run(TestRunner.java:591)

at org.testng.SuiteRunner.runTest(SuiteRunner.java:402)

at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:396)

at org.testng.SuiteRunner.privateRun(SuiteRunner.java:355)

at org.testng.SuiteRunner.run(SuiteRunner.java:304)

at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:53)

at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:96)

at org.testng.TestNG.runSuitesSequentially(TestNG.java:1180)

at org.testng.TestNG.runSuitesLocally(TestNG.java:1102)

at org.testng.TestNG.runSuites(TestNG.java:1032)

at org.testng.TestNG.run(TestNG.java:1000)

at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:115)

at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251)

at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)

===============================================

Default test

Tests run: 1, Failures: 1, Skips: 0

===============================================

Default suite

Total tests run: 1, Passes: 0, Failures: 1, Skips: 0

===============================================

ex2:

Compare boolean values:

assertEquals("ram","ram") - can be used to compare String values, boolean values, int values...etc

assertEquals(true, false);

assertEquals(10, 10); // ex of Method over loading

assertTrue(true)

assertFalse(false)

package TestNGAsserionsBasics;

import org.testng.Assert;

import org.testng.annotations.Test;

public class AssertionsBooleanValues1 {

@Test

public void testA()

{

System.out.println("test A - stmt-1");

// check true, true are equal

// Method Over loading

Assert.assertEquals(true, true);

System.out.println(" assertEquals(true, true) ");

// Pass

//- ve assert true, false

// Assert.assertEquals(true, false);

// not equals -- Fail -- stops program execution

// Fail test method name - i.e testA()

// if cond is false - it throws AssertionError

// java.lang.AssertionError: expected [false] but found [true]

// HW Assert given 10 and 10 values are equal or not

// HW Assert given 10 and 20 values are equal or not

//****************************************************

// 2.assertTrue(true) -can be used to assert given value is true

// condi - pass

Assert.assertTrue(true);

// given value is true -- Passed

// Assert.assertTrue(false);// given value is not true --Fail

// Assert.assertTrue(false); // condition - false

// it stops progr execution - it wont execute next stmt

// it throws AssertionError

//java.lang.AssertionError: did not expect to find [true] but found [false]

// also it fails test method

// 3 assertFalse() can be used to check given value is false

Assert.assertFalse(false);

System.out.println("Asserting false");

// given value is false-Passed

// -ve

// Assert.assertFalse(true);

// cond - false -- stops progr execution here - it wont execute next stm

// java.lang.AssertionError: did not expect to find [false] but found [true]

// 4 AssertNull()

System.out.println("Asserting null");

String s = null;

// assert the given value is null

Assert.assertNull(s);

// null

// pass

// null -- cond - is true -- it goes to next statement and it executes

s = "Raju";

// assert the given value is null

// Assert.assertNull(s);

// Raju

// Fail -

/// "Raju" -- cond is false - stops , throws assertion error and it wiil not execute next smt

// FAILED: testA

// java.lang.AssertionError: expected [null] but found [Raju]/

// Note : it will fail test method if assertion statement is failed

System.out.println("test A - stmt-5");

}

// HW Assert 2 int values

// Hw Assert 2 decimal values

// HW Assert 2 char values

// HW Assert 2 arrays

Assert statement with 3 args :

Assert.assertEquals(actual, expected, "Expected msg"): --MOL

Compares if the actual value is equal to the expected value and provides a custom message if the assertion fails.

package TestNGAsserionsBasics;

import org.testng.Assert;

import org.testng.annotations.Test;

public class AssertMethodsWith3Args {

@Test

public void testA()

{

System.out.println("test A - stmt-1");

//assertEquals (str1, Str2, "Expected msg")

// assert ram ram

Assert.assertEquals("ram", "ram", "Given Values are not Equals.");

// if given condition is true, it will not display the given expected message in output

// assert ram and sita and display some message if condition fails

Assert.assertEquals("ram", "sita", "Given Values are not Equal.");

// if given condition fails, it throws the given expected message in the console window // java.lang.AssertionError: Given Values are not Equal expected [sita] but found [ram] }

// assertTrue with 2 args - 2nd arg - we can pass some msg

// 5>3

Assert.assertTrue(true, "Check given value is not true");

// true

// 5<3

Assert.assertTrue(false, "Check given value is not true");

// false

// java.lang.AssertionError: Cond is false did not expect to find [true] but found [false]

// HW AssertFalse with 2 args

// HW assertNotEquals with 2 args

// HW assertNotEquals with 3 args

// Assert.assertNotEquals(0, 0, 0);

// HW AssertNotNull with 2 args

// Note : All the methods in Assert class are 'static' method

// static methods will be called by class name

// ex: className.staticMethod();

// Assert.assertTrue();

System.out.println("test A - stmt-5");

}

2.Soft Assertions :

Hard Assertion: If a hard assertion statement fails, it stops program execution and does not execute the next statement. This will also fail the test method. For example, Assert class in TestNG.

Soft Assertion: Even if an assert statement fails, it does not stop program execution and proceeds to the next statement.

package TestNGAsserionsBasics;

import org.testng.annotations.Test;

import org.testng.asserts.SoftAssert;

public class SoftAssertBasics1 {

@Test

public void testA()

{

System.out.println("test A - stmt-1");

// create obj for SoftAssert -class --> check 2 strings are equal or not Ram or Sita

// assert Ram and Ram are equal

SoftAssert sa = new SoftAssert();

sa.assertEquals("Ram", "Ram");

// Passed

// assert Ram and Sita are equal

sa.assertEquals("Ram", "Sita");

// cond is false -- Fail stmt

// even if soft assert statement fail, it does not stop program execution ,

//it does not throw Exception : AssertionError

// and it is passing the test method (no failing)

System.out.println("test A - stmt-5 got executed even if assertion failed");

}

o/p:

[RemoteTestNG] detected TestNG version 7.0.0

test A - stmt-1

test A - stmt-5

PASSED: testA

===============================================

Default test

Tests run: 1, Failures: 0, Skips: 0

===============================================

Default suite

Total tests run: 1, Passes: 1, Failures: 0, Skips: 0

===============================================

ex2:

The sa.assertAll(); statement at the end will collect all assertion results and report any failures, causing the test method to fail if any assertions did not pass. It ensures that all errors are displayed even if the test method fails.

package TestNGAsserionsBasics;

import org.testng.annotations.Test;

import org.testng.asserts.SoftAssert;

public class SoftAssertBasics1 {

@Test

public void testA()

{

System.out.println("test A - stmt-1");

// Hard assertion - if cond is fail, it stops program execution and it wont execute next stmt,

// and also it fails test method

// ex: Assert - class

// Soft assertion : even if condition is fail or false , it does not stop program execution and

// goes to next stmt

// can be used to validate condition

// create obj for SoftAssert -class --> check 2 strings are equal or not Ram or Sita

SoftAssert sa = new SoftAssert();

// assert Ram and Ram are equal

sa.assertEquals("ram", "ram");// Passed

// assert Ram and Sita are equal

sa.assertEquals("ram", "sita");// False/ Fail

// cond -is false

// even if soft assert statement fail, it does not stop program execution , it does not throw Exception : AssertionError

// and it is passing the test method (no failing)

// assert all error

// sa.assertAll();

// dont write here assertAll()

// after assertall, it wont execute any statement

System.out.println("test A - stmt-5 got executed even if assertion failed");

// If we want to display all exception in o/p and fail test method, call sa.assertAll();

// must be the last stmt

// prefer to write at the end

sa.assertAll();

// to display all errors and fail test method

System.out.println("ends ");// after assertall() - it wont execute any stmt

}

o/p:

[RemoteTestNG] detected TestNG version 7.0.0

test A - stmt-1

test A - stmt-5 got executed even if assertion failed

FAILED: testA

java.lang.AssertionError: The following asserts failed:

expected [sita] but found [ram]

at org.testng.asserts.SoftAssert.assertAll(SoftAssert.java:47)

at org.testng.asserts.SoftAssert.assertAll(SoftAssert.java:31)

at TestNgBasics2.SoftAssertionsBasics1.testA(SoftAssertionsBasics1.java:31)