[junit] java.lang.NoClassDefFoundError:

There are no useful support articles/tickets in here, so I am posting my case with hopping to get a solution.

The project was created in IntelliJ 2017 and should be all the references are added properly ( JDK, Junit ). Building in Intellj passes without errors.

The project I am running from command line, compilation passes but running the tests are failing with java.lang.NoClassDefFoundError

Here is the build.xml file I used for Ant automation framework.

<project name="Intellij_ANT_project_example">
  <property name="main.src.dir" value="src/main/java"/>
  <property name="test.src.dir" value="src/test/java"/>
  <property name="main.build.dir" value="build/"/>
  <property name="test.build.dir" value="build/"/>

  <path id="classpath.test">
    <pathelement location="lib/junit-4.12.jar"/>
    <pathelement location="lib/hamcrest-core-1.3.jar"/>
    <pathelement location="${main.build.dir}"/>
  </path>

  <target name="compile">
    <mkdir dir="${main.build.dir}"/>
    <javac srcdir="${main.src.dir}" destdir="${main.build.dir}" includeantruntime="false"/>
  </target>

  <target name="test-compile" depends="compile">
    <mkdir dir="${test.build.dir}"/>
    <javac srcdir="${test.src.dir}" destdir="${test.build.dir}" includeantruntime="false">
      <classpath refid="classpath.test"/>
    </javac>
  </target>

  <target name="test" depends="test-compile">
    <junit printsummary="on" haltonfailure="yes" fork="true">
      <classpath>
        <path refid="classpath.test"/>
        <pathelement location="${test.build.dir}/test/java"/>
      </classpath>
      <formatter type="brief" usefile="false" />
      <batchtest>
        <fileset dir="${test.src.dir}" includes="**/*Test.java" />
      </batchtest>
    </junit>
  </target>
</project>


And here is the Java source codes I used for this automation:

package main.java;

public class Calculator
{
  public int evaluate(String expression)
  {
    int sum = 0;

    for (String summand: expression.split("\\+"))
    {
      sum += Integer.valueOf(summand);
    }

    return sum;
  }
}

package test.java;

import static org.junit.Assert.assertEquals;

import main.java.Calculator;
import org.junit.Test;

public class CalculatorTest
{
  @Test
  public void evaluatesExpression()
  {
    Calculator calculator = new Calculator();
    int sum = calculator.evaluate("1+2+3");
    assertEquals(6, sum);
  }
}


while I run 'ant test' from command line I get the following output:

$ ant test
Buildfile: /home/khachatryan/Intellij_ANT_project_example/build.xml

compile:
 [javac] Compiling 1 source file to /home/khachatryan/Intellij_ANT_project_example/build

test-compile:
 [javac] Compiling 1 source file to /home/khachatryan/Intellij_ANT_project_example/build

test:
 [junit] Running CalculatorTest
 [junit] Testsuite: CalculatorTest
 [junit] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0 sec
 [junit] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0 sec
 [junit] 
 [junit] Null Test: Caused an ERROR
 [junit] CalculatorTest (wrong name: test/java/CalculatorTest)
 [junit] java.lang.NoClassDefFoundError: CalculatorTest (wrong name: test/java/CalculatorTest)
 [junit] at java.lang.ClassLoader.defineClass1(Native Method)
 [junit] at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
 [junit] at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
 [junit] at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
 [junit] at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
 [junit] at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
 [junit] at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
 [junit] at java.security.AccessController.doPrivileged(Native Method)
 [junit] at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
 [junit] at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
 [junit] at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:332)
 [junit] at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
 [junit] at java.lang.Class.forName0(Native Method)
 [junit] at java.lang.Class.forName(Class.java:265)
 [junit] 
 [junit] 

BUILD FAILED
/home/khachatryan/Intellij_ANT_project_example/build.xml:26: Test CalculatorTest failed