BaseballNumberTest.java

package baseball.domain;

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

import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.junit.jupiter.api.Test;

class BaseballNumberTest {
	@Test
	void createFromValidInput() {
		BaseballNumber number = BaseballNumber.from("123");
		assertThat(number.digits()).containsExactly(1, 2, 3);
	}

	@Test
	void rejectNullInput() {
		assertThatThrownBy(() -> BaseballNumber.from(null))
				.isInstanceOf(IllegalArgumentException.class);
	}

	@Test
	void rejectNonNumericInput() {
		assertThatThrownBy(() -> BaseballNumber.from("12a"))
				.isInstanceOf(IllegalArgumentException.class);
	}

	@Test
	void rejectWrongLength() {
		assertThatThrownBy(() -> BaseballNumber.from("12"))
				.isInstanceOf(IllegalArgumentException.class);
	}

	@Test
	void rejectZeroDigit() {
		assertThatThrownBy(() -> BaseballNumber.from("102"))
				.isInstanceOf(IllegalArgumentException.class);
	}

	@Test
	void rejectDuplicateDigits() {
		assertThatThrownBy(() -> BaseballNumber.from("112"))
				.isInstanceOf(IllegalArgumentException.class);
	}

	@Test
	void randomHasThreeUniqueDigits() {
		BaseballNumber number = BaseballNumber.random();
		List<Integer> digits = number.digits();
		assertThat(digits).hasSize(3);
		Set<Integer> unique = new HashSet<>(digits);
		assertThat(unique).hasSize(3);
		for (int digit : digits) {
			assertThat(digit).isBetween(1, 9);
		}
	}
}