JUnit默认不会控制用例的执行顺序，执行顺序由运行时查找到的用例列表的顺序决定。

如果有我们有一系列的用例，同时希望这些用例以一定的顺序执行，可以在类上添加注解：

@FixMethodOrder(MethodSorters.NAME_ASCENDING)

使JUnit以字母序列的方式执行用例。接着便是以一定的顺序，命名用例即可。

其他可选值

/**
 * Sort the methods into a specified execution order.
 * Defines common {@link MethodSorter} implementations.
 *
 * @since 4.11
 */
public enum MethodSorters {
    /**
     * Sorts the test methods by the method name, in lexicographic order,
     * with {@link Method#toString()} used as a tiebreaker
     */
    NAME_ASCENDING(MethodSorter.NAME_ASCENDING),

    /**
     * Leaves the test methods in the order returned by the JVM.
     * Note that the order from the JVM may vary from run to run
     */
    JVM(null),

    /**
     * Sorts the test methods in a deterministic, but not predictable, order
     */
    DEFAULT(MethodSorter.DEFAULT);

    private final Comparator<Method> comparator;

    private MethodSorters(Comparator<Method> comparator) {
        this.comparator = comparator;
    }

    public Comparator<Method> getComparator() {
        return comparator;
    }
}