テストでstaticメソッドに渡された引数をキャプチャーする

ArgumentCaptorSample.java

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

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

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.mockito.Matchers.any;
import static org.powermock.api.mockito.PowerMockito.doReturn;
import static org.powermock.api.mockito.PowerMockito.mock;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
import static org.powermock.api.mockito.PowerMockito.verifyStatic;

@RunWith(PowerMockRunner.class)
@PrepareForTest({Static.class})
public class ArgumentCaptorSample {

    private final Map<String, String> map = new HashMap<String, String>(){{
        put("name", "test");
        put("value", "argument captor for static method.");
    }};

    @Before
    public void setup() {
        mockStatic(Static.class);
    }

    @SuppressWarnings("unchecked")
    @Test
    public void sample() throws Exception {
        doReturn(mock(Static.class)).when(Static.class, "create", any(Map.class));

        Static obj = Static.create(map);

        verifyStatic();
        ArgumentCaptor<Map> captor = ArgumentCaptor.forClass(Map.class);
        Static.create(captor.capture());

        Map<String, String> arg = captor.getValue();

        assertNotNull(obj);
        assertEquals(map, arg);
    }
}

Static.java

import java.util.Map;
import java.util.StringJoiner;

public class Static {

    private final String name;

    private final String value;

    private Static(String name, String value){
        this.name = name;
        this.value = value;
    }

    public String getName() {
        return name;
    }

    public String getValue() {
        return value;
    }

    @Override
    public String toString() {
        return new StringJoiner(", ", "Static:[", "]")
                .add("name: [" + (name == null ? "null" : name) + "]")
                .add("value: [" + (value == null ? "null" : value) + "]")
                .toString();
    }

    public static Static create(Map<String, String> map) {
        String name = map.getOrDefault("name", "");
        String value = map.getOrDefault("value", "");
        return new Static(name, value);
    }
}