library/alloc/tests/fmt.rs - toolchain/rustc - Git at Google

 #![deny(warnings)]
 // FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
 #![allow(static_mut_refs)]

 use std::cell::RefCell;
 use std::fmt::{self, Write};
 use std::ptr;

 #[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\0bar\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}", ptr::without_provenance::<isize>(0x1234)), "0x00001234");
         t!(format!("{:#p}", ptr::without_provenance_mut::<isize>(0x1234)), "0x00001234");
     } else {
         t!(format!("{:#p}", ptr::without_provenance::<isize>(0x1234)), "0x0000000000001234");
         t!(format!("{:#p}", ptr::without_provenance_mut::<isize>(0x1234)), "0x0000000000001234");
     }
     t!(format!("{:p}", ptr::without_provenance::<isize>(0x1234)), "0x1234");
     t!(format!("{:p}", ptr::without_provenance_mut::<isize>(0x1234)), "0x1234");
     t!(format!("{A:x}"), "aloha");
     t!(format!("{B:X}"), "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!("{C:#4}"), "☃123");
     t!(format!("{D:b}"), "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");

     // 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!("{val:#x}");
         t!(format!("{:p}", std::ptr::without_provenance::<isize>(val)), exp);
     }

     // Escaping
     t!(format!("{{"), "{");
     t!(format!("}}"), "}");

     // make sure that format! doesn't move out of local variables
     let a = Box::new(3);
     let _ = format!("{a}");
     let _ = 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);
         let _ = format!("{a}");
     }

     // test that trailing commas are acceptable
     let _ = format!("{}", "test",);
     let _ = 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 }");
 }
	#![deny(warnings)]
	// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
	#![allow(static_mut_refs)]

	use std::cell::RefCell;
	use std::fmt::{self, Write};
	use std::ptr;

	#[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\0bar\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}", ptr::without_provenance::<isize>(0x1234)), "0x00001234");
	t!(format!("{:#p}", ptr::without_provenance_mut::<isize>(0x1234)), "0x00001234");
	} else {
	t!(format!("{:#p}", ptr::without_provenance::<isize>(0x1234)), "0x0000000000001234");
	t!(format!("{:#p}", ptr::without_provenance_mut::<isize>(0x1234)), "0x0000000000001234");
	}
	t!(format!("{:p}", ptr::without_provenance::<isize>(0x1234)), "0x1234");
	t!(format!("{:p}", ptr::without_provenance_mut::<isize>(0x1234)), "0x1234");
	t!(format!("{A:x}"), "aloha");
	t!(format!("{B:X}"), "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!("{C:#4}"), "☃123");
	t!(format!("{D:b}"), "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");

	// 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!("{val:#x}");
	t!(format!("{:p}", std::ptr::without_provenance::<isize>(val)), exp);
	}

	// Escaping
	t!(format!("{{"), "{");
	t!(format!("}}"), "}");

	// make sure that format! doesn't move out of local variables
	let a = Box::new(3);
	let _ = format!("{a}");
	let _ = 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);
	let _ = format!("{a}");
	}

	// test that trailing commas are acceptable
	let _ = format!("{}", "test",);
	let _ = 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 }");
	}