Tests

src/vga_buffer.rs

@@ -125,38 +125,25 @@ impl fmt::Write for Writer {
     }
 }
 
-lazy_static! {
-    pub static ref WRITER: Mutex<Writer> = Mutex::new(Writer {
+// 将 Writer 设置为静态以便调用
+lazy_static! {  // 内置的 static 会用到标准库里的一些东西，所以这里用 lazy_static
+    pub static ref WRITER: Mutex<Writer> = Mutex::new(Writer {  // 用互斥锁来防止冲突
         column_position: 0,
         color_code: ColorCode::new(Color::Yellow, Color::Black),
         buffer: unsafe { &mut *(0xb8000 as *mut Buffer) }
     });
 }
 
-pub fn print_something() {
-    use core::fmt::Write;
-    let mut writer = Writer {
-        column_position: 0,
-        color_code: ColorCode::new(Color::Yellow, Color::Black),
-        // VGA Buffer 从 0xb8000 开始
-        buffer: unsafe { &mut *(0xb8000 as *mut Buffer) },
-    };
-    writer.write_byte(b'H');
-    writer.write_string("ello ");
-    writer.write_string("Wörld!");
-    write!(writer, "The numbers are {} and {}", 42, 1.0/3.0).unwrap();
-}
-
 // 将宏导出到 crate 的根，这样我们就可以用
 // use crate::println
 // 来使用它
 #[macro_export]
-macro_rules! print {
+macro_rules! print {    // print!()
     ($($arg:tt)*) => ($crate::vga_buffer::_print(format_args!($($arg)*)));
 }
 
 #[macro_export]
-macro_rules! println {
+macro_rules! println {  // println!()
     () => ($crate::print!("\n"));
     ($($arg:tt)*) => ($crate::print!("{}\n", format_args!($($arg)*)));
 }
@@ -168,3 +155,25 @@ pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
     WRITER.lock().write_fmt(args).unwrap();
 }
+
+#[test_case]
+fn test_println_simple() {  // 测试单行 println!
+    println!("test_println_simple output");
+}
+
+#[test_case]
+fn test_println_many() {    // 测试多行 println!
+    for _ in 0..100 {
+        println!("test_println_many output");
+    }
+}
+
+#[test_case]
+fn test_println_output() {  // 测试字符是否真的打印到了屏幕上
+    let s = "Some test string that fits on a single line";
+    println!("{}", s);
+    for (i, c) in s.chars().enumerate() {
+        let screen_char = WRITER.lock().buffer.chars[BUFFER_HEIGHT - 2][i].read();
+        assert_eq!(char::from(screen_char.ascii_character), c);
+    }
+}