MoshiAutoValueTest.java

package io.github.ktchernov.moshiautovaluebug;

import com.squareup.moshi.Moshi;

import org.junit.Before;
import org.junit.Test;

import io.github.ktchernov.moshiautovaluebug.TestClassA.TestClassB;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;

public class MoshiAutoValueTest {

	private Moshi moshi;

	@Before public void setUp() {
		moshi = new Moshi.Builder()
				.add(TestClassB.typeAdapterFactory()).build();
	}

	@Test
	public void parseValid() throws Exception {
		TestClassA testClassA =
				moshi.adapter(TestClassA.class).fromJson("{ \"data\": { \"someValue\": 1 }");

		assertEquals(1, testClassA.data.someValue());
	}

	@Test
	public void parseWithNull() throws Exception {
		TestClassA testClassA =
				moshi.adapter(TestClassA.class).fromJson("{ \"data\": null }");

		assertNull(testClassA.data);
	}

}

TestClassA.java

package io.github.ktchernov.moshiautovaluebug;

import com.google.auto.value.AutoValue;

import android.support.annotation.Nullable;

import com.squareup.moshi.JsonAdapter;

public class TestClassA {
	@Nullable public TestClassB data;

	@AutoValue public static abstract class TestClassB {
		public abstract int someValue();

		public static JsonAdapter.Factory typeAdapterFactory() {
			return AutoValue_TestClassA_TestClassB.typeAdapterFactory();
		}
	}
}