Junit spy static method.

Foo.java

public class Foo {

    public static String testMethod() {
        return "foo";
    }

}

Snipets.java

import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.fail;

import java.util.HashMap;
import java.util.Map;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest({Foo.class })
public class Snipets {

    @Test
    public void hoge() throws Exception {

        PowerMockito.spy(Foo.class);
        PowerMockito.when(Foo.class, "testMethod").thenReturn("dummy");

        String actual = Foo.testMethod();
        assertEquals("dummy", actual);
    }

}