AmountsTest.java

package io.konik.util;

import com.neovisionaries.i18n.CurrencyCode;
import io.konik.zugferd.unqualified.Amount;
import org.junit.Test;

import java.math.BigDecimal;

import static org.assertj.core.api.Assertions.assertThat;

public class AmountsTest {

	@Test(expected = IllegalArgumentException.class)
	public void shouldThrowIllegalArgumentExceptionIfFirstAmountIsNull() {
		//when:
		Amounts.add(null, null);
	}

	@Test(expected = IllegalArgumentException.class)
	public void shouldThrowIllegalArgumentExceptionIfAmountsHaveDifferentCurrencies() {
		//when:
		Amounts.add(Amounts.zero(CurrencyCode.USD), Amounts.zero(CurrencyCode.EUR));
	}

	@Test
	public void shouldTreatNullValueAsZeroWhenAddingToNonNullAmountAsAFirstParameter() {
		//given:
		Amount amount = new Amount(BigDecimal.valueOf(43.55), CurrencyCode.USD);
		//when:
		Amount result = Amounts.add(amount, null);
		//then:
		assertThat(result).isEqualToComparingFieldByField(amount);
	}

	@Test
	public void shouldTreatNullValueAsZeroWhenAddingToNonNullAmountAsASecondParameter() {
		//given:
		Amount amount = new Amount(BigDecimal.valueOf(43.55), CurrencyCode.USD);
		//when:
		Amount result = Amounts.add(null, amount);
		//then:
		assertThat(result).isEqualToComparingFieldByField(amount);
	}
}