{"id":25195,"date":"2015-07-17T11:00:33","date_gmt":"2015-07-17T08:00:33","guid":{"rendered":"http:\/\/examples.javacodegeeks.com\/?p=25195"},"modified":"2019-03-21T12:34:12","modified_gmt":"2019-03-21T10:34:12","slug":"junit-assertthat-example","status":"publish","type":"post","link":"https:\/\/examples.javacodegeeks.com\/java-development\/core-java\/junit\/junit-assertthat-example\/","title":{"rendered":"JUnit AssertThat Example"},"content":{"rendered":"

1. Introduction<\/h2>\n

The assertThat<\/a><\/code> is one of the JUnit methods from the Assert object that can be used to check if a specific value match to an expected one.<\/p>\n

It primarily accepts 2 parameters. First one if the actual value and the second is a matcher object. It will then try to compare this two and returns a boolean result if its a match or not. Example of it’s usage as per below.
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2. The Source Code<\/h2>\n

JUnitTestAssertThatAssertions.java<\/em><\/span><\/p>\n

package com.areyes1.junitassertrue.sample;\n\nimport static org.junit.Assert.*;\nimport static org.hamcrest.CoreMatchers.*;\nimport org.junit.Before;\nimport org.junit.Test;\n\npublic class JUnitTestAssertThatAssertions {\n\t\n\tint totalNumberOfApplicants = 0;\n\t\n\t@Before\n\tpublic void setData(){\n\t\tthis.totalNumberOfApplicants = 9;\n\t}\n\t\n\t@Test\n\tpublic void testAssertThatEqual() {\n\t\tassertThat(\"123\",is(\"123\"));\n\t}\n\t\n\t@Test\n\tpublic void testAssertThatNotEqual() {\n\t\tassertThat(totalNumberOfApplicants,is(123));\n\t}\n\t\n\t@Test\n\tpublic void testAssertThatObject() {\n\t\tassertThat(\"123\",isA(String.class));\n\t}\n\t\n\t@Test\n\tpublic void testAssertThatWMessage(){\n\t\tassertThat(\"They are not equal!\",\"123\",is(\"1234\"));\n\t}\n}\n\n\n<\/pre>\n
The example shown above uses is<\/a><\/code> and isA<\/a><\/code> method from the hamcrest core to return a matcher object given the value. This is then used by the assertThat<\/a> method that will then return a boolean result of the comparison.<\/p>\n
Here’s the output:<\/p>\n
\"Figure<\/a>
Figure 1.0 AssertThat output<\/figcaption><\/figure>
 
<\/div> <\/div><\/p>\n
Aside from the example above, there are far more methods that can be used to rigorously test one’s code. JUnits own hamcrest api has incorporate core, logical and object methods for this purpose.<\/p>\n
2.1 Core Matchers<\/h3>\n
Before you start implementing your own Matcher’s, you should look at the core matchers that come with JUnit already. Here is a list of the matcher methods:<\/p>\n
Core<\/h4>\n