Rollup merge of rust-lang#76454 - poliorcetics:ui-to-unit-test-1, r=m…

…atklad

UI to unit test for those using Cell/RefCell/UnsafeCell

Helps with rust-lang#76268.

I'm working on all files using `Cell` and moving them to unit tests when possible.

r? @matklad

library/alloc/tests/boxed.rs

@@ -1,3 +1,4 @@
+use std::cell::Cell;
 use std::mem::MaybeUninit;
 use std::ptr::NonNull;
 
@@ -49,3 +50,10 @@ fn box_clone_from_ptr_stability() {
         assert_eq!(copy.as_ptr() as usize, copy_raw);
     }
 }
+
+#[test]
+fn box_deref_lval() {
+    let x = Box::new(Cell::new(5));
+    x.set(1000);
+    assert_eq!(x.get(), 1000);
+}

library/alloc/tests/fmt.rs

@@ -1,7 +1,327 @@
-use std::fmt;
+#![deny(warnings)]
+
+use std::cell::RefCell;
+use std::fmt::{self, Write};
 
 #[test]
 fn test_format() {
     let s = fmt::format(format_args!("Hello, {}!", "world"));
     assert_eq!(s, "Hello, world!");
 }
+
+struct A;
+struct B;
+struct C;
+struct D;
+
+impl fmt::LowerHex for A {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("aloha")
+    }
+}
+impl fmt::UpperHex for B {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("adios")
+    }
+}
+impl fmt::Display for C {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.pad_integral(true, "☃", "123")
+    }
+}
+impl fmt::Binary for D {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("aa")?;
+        f.write_char('☃')?;
+        f.write_str("bb")
+    }
+}
+
+macro_rules! t {
+    ($a:expr, $b:expr) => {
+        assert_eq!($a, $b)
+    };
+}
+
+#[test]
+fn test_format_macro_interface() {
+    // Various edge cases without formats
+    t!(format!(""), "");
+    t!(format!("hello"), "hello");
+    t!(format!("hello {{"), "hello {");
+
+    // default formatters should work
+    t!(format!("{}", 1.0f32), "1");
+    t!(format!("{}", 1.0f64), "1");
+    t!(format!("{}", "a"), "a");
+    t!(format!("{}", "a".to_string()), "a");
+    t!(format!("{}", false), "false");
+    t!(format!("{}", 'a'), "a");
+
+    // At least exercise all the formats
+    t!(format!("{}", true), "true");
+    t!(format!("{}", '☃'), "☃");
+    t!(format!("{}", 10), "10");
+    t!(format!("{}", 10_usize), "10");
+    t!(format!("{:?}", '☃'), "'☃'");
+    t!(format!("{:?}", 10), "10");
+    t!(format!("{:?}", 10_usize), "10");
+    t!(format!("{:?}", "true"), "\"true\"");
+    t!(format!("{:?}", "foo\nbar"), "\"foo\\nbar\"");
+    t!(
+        format!("{:?}", "foo\n\"bar\"\r\n\'baz\'\t\\qux\\"),
+        r#""foo\n\"bar\"\r\n\'baz\'\t\\qux\\""#
+    );
+    t!(format!("{:?}", "foo\0bar\x01baz\u{7f}q\u{75}x"), r#""foo\u{0}bar\u{1}baz\u{7f}qux""#);
+    t!(format!("{:o}", 10_usize), "12");
+    t!(format!("{:x}", 10_usize), "a");
+    t!(format!("{:X}", 10_usize), "A");
+    t!(format!("{}", "foo"), "foo");
+    t!(format!("{}", "foo".to_string()), "foo");
+    if cfg!(target_pointer_width = "32") {
+        t!(format!("{:#p}", 0x1234 as *const isize), "0x00001234");
+        t!(format!("{:#p}", 0x1234 as *mut isize), "0x00001234");
+    } else {
+        t!(format!("{:#p}", 0x1234 as *const isize), "0x0000000000001234");
+        t!(format!("{:#p}", 0x1234 as *mut isize), "0x0000000000001234");
+    }
+    t!(format!("{:p}", 0x1234 as *const isize), "0x1234");
+    t!(format!("{:p}", 0x1234 as *mut isize), "0x1234");
+    t!(format!("{:x}", A), "aloha");
+    t!(format!("{:X}", B), "adios");
+    t!(format!("foo {} ☃☃☃☃☃☃", "bar"), "foo bar ☃☃☃☃☃☃");
+    t!(format!("{1} {0}", 0, 1), "1 0");
+    t!(format!("{foo} {bar}", foo = 0, bar = 1), "0 1");
+    t!(format!("{foo} {1} {bar} {0}", 0, 1, foo = 2, bar = 3), "2 1 3 0");
+    t!(format!("{} {0}", "a"), "a a");
+    t!(format!("{_foo}", _foo = 6usize), "6");
+    t!(format!("{foo_bar}", foo_bar = 1), "1");
+    t!(format!("{}", 5 + 5), "10");
+    t!(format!("{:#4}", C), "☃123");
+    t!(format!("{:b}", D), "aa☃bb");
+
+    let a: &dyn fmt::Debug = &1;
+    t!(format!("{:?}", a), "1");
+
+    // Formatting strings and their arguments
+    t!(format!("{}", "a"), "a");
+    t!(format!("{:4}", "a"), "a   ");
+    t!(format!("{:4}", "☃"), "☃   ");
+    t!(format!("{:>4}", "a"), "   a");
+    t!(format!("{:<4}", "a"), "a   ");
+    t!(format!("{:^5}", "a"), "  a  ");
+    t!(format!("{:^5}", "aa"), " aa  ");
+    t!(format!("{:^4}", "a"), " a  ");
+    t!(format!("{:^4}", "aa"), " aa ");
+    t!(format!("{:.4}", "a"), "a");
+    t!(format!("{:4.4}", "a"), "a   ");
+    t!(format!("{:4.4}", "aaaaaaaaaaaaaaaaaa"), "aaaa");
+    t!(format!("{:<4.4}", "aaaaaaaaaaaaaaaaaa"), "aaaa");
+    t!(format!("{:>4.4}", "aaaaaaaaaaaaaaaaaa"), "aaaa");
+    t!(format!("{:^4.4}", "aaaaaaaaaaaaaaaaaa"), "aaaa");
+    t!(format!("{:>10.4}", "aaaaaaaaaaaaaaaaaa"), "      aaaa");
+    t!(format!("{:2.4}", "aaaaa"), "aaaa");
+    t!(format!("{:2.4}", "aaaa"), "aaaa");
+    t!(format!("{:2.4}", "aaa"), "aaa");
+    t!(format!("{:2.4}", "aa"), "aa");
+    t!(format!("{:2.4}", "a"), "a ");
+    t!(format!("{:0>2}", "a"), "0a");
+    t!(format!("{:.*}", 4, "aaaaaaaaaaaaaaaaaa"), "aaaa");
+    t!(format!("{:.1$}", "aaaaaaaaaaaaaaaaaa", 4), "aaaa");
+    t!(format!("{:.a$}", "aaaaaaaaaaaaaaaaaa", a = 4), "aaaa");
+    t!(format!("{:._a$}", "aaaaaaaaaaaaaaaaaa", _a = 4), "aaaa");
+    t!(format!("{:1$}", "a", 4), "a   ");
+    t!(format!("{1:0$}", 4, "a"), "a   ");
+    t!(format!("{:a$}", "a", a = 4), "a   ");
+    t!(format!("{:-#}", "a"), "a");
+    t!(format!("{:+#}", "a"), "a");
+    t!(format!("{:/^10.8}", "1234567890"), "/12345678/");
+
+    // Some float stuff
+    t!(format!("{:}", 1.0f32), "1");
+    t!(format!("{:}", 1.0f64), "1");
+    t!(format!("{:.3}", 1.0f64), "1.000");
+    t!(format!("{:10.3}", 1.0f64), "     1.000");
+    t!(format!("{:+10.3}", 1.0f64), "    +1.000");
+    t!(format!("{:+10.3}", -1.0f64), "    -1.000");
+
+    t!(format!("{:e}", 1.2345e6f32), "1.2345e6");
+    t!(format!("{:e}", 1.2345e6f64), "1.2345e6");
+    t!(format!("{:E}", 1.2345e6f64), "1.2345E6");
+    t!(format!("{:.3e}", 1.2345e6f64), "1.234e6");
+    t!(format!("{:10.3e}", 1.2345e6f64), "   1.234e6");
+    t!(format!("{:+10.3e}", 1.2345e6f64), "  +1.234e6");
+    t!(format!("{:+10.3e}", -1.2345e6f64), "  -1.234e6");
+
+    // Float edge cases
+    t!(format!("{}", -0.0), "0");
+    t!(format!("{:?}", -0.0), "-0.0");
+    t!(format!("{:?}", 0.0), "0.0");
+
+    // sign aware zero padding
+    t!(format!("{:<3}", 1), "1  ");
+    t!(format!("{:>3}", 1), "  1");
+    t!(format!("{:^3}", 1), " 1 ");
+    t!(format!("{:03}", 1), "001");
+    t!(format!("{:<03}", 1), "001");
+    t!(format!("{:>03}", 1), "001");
+    t!(format!("{:^03}", 1), "001");
+    t!(format!("{:+03}", 1), "+01");
+    t!(format!("{:<+03}", 1), "+01");
+    t!(format!("{:>+03}", 1), "+01");
+    t!(format!("{:^+03}", 1), "+01");
+    t!(format!("{:#05x}", 1), "0x001");
+    t!(format!("{:<#05x}", 1), "0x001");
+    t!(format!("{:>#05x}", 1), "0x001");
+    t!(format!("{:^#05x}", 1), "0x001");
+    t!(format!("{:05}", 1.2), "001.2");
+    t!(format!("{:<05}", 1.2), "001.2");
+    t!(format!("{:>05}", 1.2), "001.2");
+    t!(format!("{:^05}", 1.2), "001.2");
+    t!(format!("{:05}", -1.2), "-01.2");
+    t!(format!("{:<05}", -1.2), "-01.2");
+    t!(format!("{:>05}", -1.2), "-01.2");
+    t!(format!("{:^05}", -1.2), "-01.2");
+    t!(format!("{:+05}", 1.2), "+01.2");
+    t!(format!("{:<+05}", 1.2), "+01.2");
+    t!(format!("{:>+05}", 1.2), "+01.2");
+    t!(format!("{:^+05}", 1.2), "+01.2");
+
+    // Ergonomic format_args!
+    t!(format!("{0:x} {0:X}", 15), "f F");
+    t!(format!("{0:x} {0:X} {}", 15), "f F 15");
+    t!(format!("{:x}{0:X}{a:x}{:X}{1:x}{a:X}", 13, 14, a = 15), "dDfEeF");
+    t!(format!("{a:x} {a:X}", a = 15), "f F");
+
+    // And its edge cases
+    t!(
+        format!(
+            "{a:.0$} {b:.0$} {0:.0$}\n{a:.c$} {b:.c$} {c:.c$}",
+            4,
+            a = "abcdefg",
+            b = "hijklmn",
+            c = 3
+        ),
+        "abcd hijk 4\nabc hij 3"
+    );
+    t!(format!("{a:.*} {0} {:.*}", 4, 3, "efgh", a = "abcdef"), "abcd 4 efg");
+    t!(format!("{:.a$} {a} {a:#x}", "aaaaaa", a = 2), "aa 2 0x2");
+
+    // Test that pointers don't get truncated.
+    {
+        let val = usize::MAX;
+        let exp = format!("{:#x}", val);
+        t!(format!("{:p}", val as *const isize), exp);
+    }
+
+    // Escaping
+    t!(format!("{{"), "{");
+    t!(format!("}}"), "}");
+
+    // make sure that format! doesn't move out of local variables
+    let a = Box::new(3);
+    format!("{}", a);
+    format!("{}", a);
+
+    // make sure that format! doesn't cause spurious unused-unsafe warnings when
+    // it's inside of an outer unsafe block
+    unsafe {
+        let a: isize = ::std::mem::transmute(3_usize);
+        format!("{}", a);
+    }
+
+    // test that trailing commas are acceptable
+    format!("{}", "test",);
+    format!("{foo}", foo = "test",);
+}
+
+// Basic test to make sure that we can invoke the `write!` macro with an
+// fmt::Write instance.
+#[test]
+fn test_write() {
+    let mut buf = String::new();
+    let _ = write!(&mut buf, "{}", 3);
+    {
+        let w = &mut buf;
+        let _ = write!(w, "{foo}", foo = 4);
+        let _ = write!(w, "{}", "hello");
+        let _ = writeln!(w, "{}", "line");
+        let _ = writeln!(w, "{foo}", foo = "bar");
+        let _ = w.write_char('☃');
+        let _ = w.write_str("str");
+    }
+
+    t!(buf, "34helloline\nbar\n☃str");
+}
+
+// Just make sure that the macros are defined, there's not really a lot that we
+// can do with them just yet (to test the output)
+#[test]
+fn test_print() {
+    print!("hi");
+    print!("{:?}", vec![0u8]);
+    println!("hello");
+    println!("this is a {}", "test");
+    println!("{foo}", foo = "bar");
+}
+
+// Just make sure that the macros are defined, there's not really a lot that we
+// can do with them just yet (to test the output)
+#[test]
+fn test_format_args() {
+    let mut buf = String::new();
+    {
+        let w = &mut buf;
+        let _ = write!(w, "{}", format_args!("{}", 1));
+        let _ = write!(w, "{}", format_args!("test"));
+        let _ = write!(w, "{}", format_args!("{test}", test = 3));
+    }
+    let s = buf;
+    t!(s, "1test3");
+
+    let s = fmt::format(format_args!("hello {}", "world"));
+    t!(s, "hello world");
+    let s = format!("{}: {}", "args were", format_args!("hello {}", "world"));
+    t!(s, "args were: hello world");
+}
+
+#[test]
+fn test_order() {
+    // Make sure format!() arguments are always evaluated in a left-to-right
+    // ordering
+    fn foo() -> isize {
+        static mut FOO: isize = 0;
+        unsafe {
+            FOO += 1;
+            FOO
+        }
+    }
+    assert_eq!(
+        format!("{} {} {a} {b} {} {c}", foo(), foo(), foo(), a = foo(), b = foo(), c = foo()),
+        "1 2 4 5 3 6".to_string()
+    );
+}
+
+#[test]
+fn test_once() {
+    // Make sure each argument are evaluated only once even though it may be
+    // formatted multiple times
+    fn foo() -> isize {
+        static mut FOO: isize = 0;
+        unsafe {
+            FOO += 1;
+            FOO
+        }
+    }
+    assert_eq!(format!("{0} {0} {0} {a} {a} {a}", foo(), a = foo()), "1 1 1 2 2 2".to_string());
+}
+
+#[test]
+fn test_refcell() {
+    let refcell = RefCell::new(5);
+    assert_eq!(format!("{:?}", refcell), "RefCell { value: 5 }");
+    let borrow = refcell.borrow_mut();
+    assert_eq!(format!("{:?}", refcell), "RefCell { value: <borrowed> }");
+    drop(borrow);
+    assert_eq!(format!("{:?}", refcell), "RefCell { value: 5 }");
+}