test: 测试工具类的私有构造器

src/test/java/xyz/zhouxy/plusone/commons/util/NumbersTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2024 the original author or authors.
+ * Copyright 2024-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,9 +17,16 @@
 package xyz.zhouxy.plusone.commons.util;
 
 import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Constructor;
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.util.Arrays;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 public
 class NumbersTests {
@@ -184,4 +191,18 @@ class NumbersTests {
         BigDecimal result = Numbers.nullToZero(value);
         assertEquals(BigDecimal.ZERO, result);
     }
+
+    @Test
+    void test_constructor_isNotAccessible_ThrowsIllegalStateException() {
+        Constructor<?>[] constructors = Numbers.class.getDeclaredConstructors();
+        Arrays.stream(constructors)
+                .forEach(constructor -> {
+                    assertFalse(constructor.isAccessible());
+                    constructor.setAccessible(true);
+                    Throwable cause = assertThrows(Exception.class, constructor::newInstance)
+                            .getCause();
+                    assertInstanceOf(IllegalStateException.class, cause);
+                    assertEquals("Utility class", cause.getMessage());
+                });
+    }
 }