完善单元测试。

src/test/java/xyz/zhouxy/plusone/commons/base/YearQuarterTests.java

@@ -0,0 +1,55 @@
+package xyz.zhouxy.plusone.commons.base;
+
+import org.junit.jupiter.api.Test;
+
+import lombok.extern.slf4j.Slf4j;
+
+import java.time.LocalDate;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+@Slf4j
+public class YearQuarterTests {
+
+    @Test
+    void of_ValidYearAndQuarter_CreatesYearQuarter() {
+        int year = 2023;
+        Quarter quarter = Quarter.Q1;
+
+        YearQuarter expected = YearQuarter.of(year, quarter);
+        YearQuarter actual = YearQuarter.of(LocalDate.of(year, 2, 28));
+
+        assertEquals(expected, actual);
+
+        assertEquals("Q1 2023", actual.toString());
+    }
+
+    @Test
+    @SuppressWarnings("null")
+    void of_InvalidQuarter_ThrowsNullPointerException() {
+        int year = 2023;
+        Quarter quarter = null;
+
+        assertThrows(NullPointerException.class, () -> YearQuarter.of(year, quarter));
+    }
+
+    @Test
+    void of_ValidYearQuarter_GetsCorrectStartAndEndDate() {
+
+        for (int year = 1990; year <= 2024; year++) {
+            for (int qrtr = 1; qrtr <= 4; qrtr++) {
+                Quarter quarter = Quarter.of(qrtr);
+                YearQuarter yearQuarter = YearQuarter.of(year, quarter);
+
+                LocalDate expectedStartDate = quarter.getStartMonthDay().atYear(year);
+                log.info("{} - expectedStartDate: {}", yearQuarter, expectedStartDate);
+                LocalDate expectedEndDate = quarter.getLastMonthDay().atYear(year);
+                log.info("{} - expectedEndDate: {}", yearQuarter, expectedEndDate);
+                
+                assertEquals(expectedStartDate, yearQuarter.getStartDate());
+                assertEquals(expectedEndDate, yearQuarter.getLastDate());
+            }
+        }
+    }
+}