How to use assertTrue?

问题:

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.

回答1:

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);
   }
}

回答2:

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.

回答3:

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.

回答4:

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)));
}