How to use assertTrue?

Question

I have:

package com.darlik.test; import org.junit.Assert; public class Test { public static void main(String[] args) { assertTrue(1, 2); } }

package with org.junit is set and working but in line with assertTrue i have error:

The method assertTrue(int, int) is undefined for the type Test

Why? I use Eclipse.

assertTrue has the method signature assertTrue(boolean), i.e. assertTrue(actual == expected), see junit.sourceforge.net/javadoc/org/junit/… — jdphenix
– jdphenix, Commented Aug 17, 2014 at 18:31
why use main? Please annotate with test, makes more sense, even in example. Second thing, you don't have appropriate import. Please fix import as suggested by @Reimeus + change what you are comparing inside — Michal Gruca
– Michal Gruca, Commented Aug 17, 2014 at 18:55
@MichalGruca Good point - also remember to rename the class since it conflicts with org.junit.Test — Reimeus
– Reimeus, Commented Aug 17, 2014 at 19:04

Reimeus · Accepted Answer · 2014-08-17 19:04:04Z

assertTrue is based on a single boolean condition. For example

assertTrue(1 == 2);

You need to import the statement statically to use

import static org.junit.Assert.assertTrue;

Typically, however assertEquals is used when comparing 2 parameters, e.g.

public class MyTest { @Test public void testAssert() throws Exception { assertEquals(1, 2); } }

m4rtin · Accepted Answer · 2014-08-17 18:31:43Z

From the doc : assertTrue(boolean) or assertTrue(String, boolean) if you want to add a message.

AssertTrue assert that a condition is true, you still have to code such condition for it to be evaluated at runtime.

Jeroen Vannevel · Accepted Answer · 2014-08-17 18:37:00Z

You have to specify the class that defines that method:

Assert.assertTrue(condition);

Furthermore you're calling the method with 2 parameters which makes no sense. assertTrue expects a single boolean expression.

Although you can also do this by using a static import:

import static org.junit.Assert.*;

which will allow you to call it as assertTrue(condition); instead.

Prakash · Accepted Answer · 2016-08-16 18:55:09Z

Better try assertThat with matchers. Check this blog about it https://objectpartners.com/2013/09/18/the-benefits-of-using-assertthat-over-other-assert-methods-in-unit-tests/

import static org.hamcrest.Matchers.equalTo; import static org.hamcrest.Matchers.is; import static org.junit.Assert.assertThat; .... @Test public void testNum() { assertThat(repo.getNum(), is(equalTo(111))); }

Salman Shokha · Accepted Answer · 2020-12-25 04:35:50Z

Delete the module-info.java file if there is any in the project. It's not necessary and is only used if you're using Java's built-in module system.

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