package com.example;

import static org.junit.jupiter.api.Assertions.assertEquals;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

public class MainTest {
    @Test
    @DisplayName("checkString returns 'Input is null.' for null input")
    void testNullInput() {
        assertEquals("Input is null.", Main.checkString(null), "Should return 'Input is null.' for null input");
    }

    @Test
    @DisplayName("checkString returns 'Input is empty.' for empty input")
    void testEmptyInput() {
        assertEquals("Input is empty.", Main.checkString(""), "Should return 'Input is empty.' for empty input");
    }

    @Test
    @DisplayName("checkString returns correct message for non-empty input: Hello world")
    void testNonEmptyInputHelloWorld() {
        assertEquals("Input is: Hello world", Main.checkString("Hello world"), "Should return 'Input is: Hello world' for input 'Hello world'");
    }

    @Test
    @DisplayName("checkString returns correct message for non-empty input: test123")
    void testNonEmptyInputTest123() {
        assertEquals("Input is: test123", Main.checkString("test123"), "Should return 'Input is: test123' for input 'test123'");
    }

    @Test
    @DisplayName("checkString returns correct message for whitespace input")
    void testWhitespaceInput() {
        assertEquals("Input is:   ", Main.checkString("  "), "Should return 'Input is:   ' for input with spaces");
    }
}


MainTest.java

A comprehensive course on Java data types, covering primitives, reference types, type conversion, and practical applications. Designed for learners with basic Java syntax knowledge.

Explore Java's built-in primitive data types, their properties, and how to use them effectively.

Delve into Java's reference types, focusing on Strings and arrays, and how they differ from primitives.

Learn about type casting, automatic conversions, and the use of wrapper classes for primitives.

Challenge: Null Reference Handling

解答