library/core/tests/option.rs

   1 use core::cell::Cell;
   2 use core::clone::Clone;
   3 use core::mem;
   4 use core::ops::DerefMut;
   5 use core::option::*;
   6
   7 #[test]
   8 fn test_get_ptr() {
   9     unsafe {
  10         let x: Box<_> = box 0;
  11         let addr_x: *const isize = mem::transmute(&*x);
  12         let opt = Some(x);
  13         let y = opt.unwrap();
  14         let addr_y: *const isize = mem::transmute(&*y);
  15         assert_eq!(addr_x, addr_y);
  16     }
  17 }
  18
  19 #[test]
  20 fn test_get_str() {
  21     let x = "test".to_string();
  22     let addr_x = x.as_ptr();
  23     let opt = Some(x);
  24     let y = opt.unwrap();
  25     let addr_y = y.as_ptr();
  26     assert_eq!(addr_x, addr_y);
  27 }
  28
  29 #[test]
  30 fn test_get_resource() {
  31     use core::cell::RefCell;
  32     use std::rc::Rc;
  33
  34     struct R {
  35         i: Rc<RefCell<isize>>,
  36     }
  37
  38     impl Drop for R {
  39         fn drop(&mut self) {
  40             let ii = &*self.i;
  41             let i = *ii.borrow();
  42             *ii.borrow_mut() = i + 1;
  43         }
  44     }
  45
  46     fn r(i: Rc<RefCell<isize>>) -> R {
  47         R { i }
  48     }
  49
  50     let i = Rc::new(RefCell::new(0));
  51     {
  52         let x = r(i.clone());
  53         let opt = Some(x);
  54         let _y = opt.unwrap();
  55     }
  56     assert_eq!(*i.borrow(), 1);
  57 }
  58
  59 #[test]
  60 fn test_option_dance() {
  61     let x = Some(());
  62     let mut y = Some(5);
  63     let mut y2 = 0;
  64     for _x in x {
  65         y2 = y.take().unwrap();
  66     }
  67     assert_eq!(y2, 5);
  68     assert!(y.is_none());
  69 }
  70
  71 #[test]
  72 #[should_panic]
  73 fn test_option_too_much_dance() {
  74     struct A;
  75     let mut y = Some(A);
  76     let _y2 = y.take().unwrap();
  77     let _y3 = y.take().unwrap();
  78 }
  79
  80 #[test]
  81 fn test_and() {
  82     let x: Option<isize> = Some(1);
  83     assert_eq!(x.and(Some(2)), Some(2));
  84     assert_eq!(x.and(None::<isize>), None);
  85
  86     let x: Option<isize> = None;
  87     assert_eq!(x.and(Some(2)), None);
  88     assert_eq!(x.and(None::<isize>), None);
  89 }
  90
  91 #[test]
  92 fn test_and_then() {
  93     let x: Option<isize> = Some(1);
  94     assert_eq!(x.and_then(|x| Some(x + 1)), Some(2));
  95     assert_eq!(x.and_then(|_| None::<isize>), None);
  96
  97     let x: Option<isize> = None;
  98     assert_eq!(x.and_then(|x| Some(x + 1)), None);
  99     assert_eq!(x.and_then(|_| None::<isize>), None);
 100 }
 101
 102 #[test]
 103 fn test_or() {
 104     let x: Option<isize> = Some(1);
 105     assert_eq!(x.or(Some(2)), Some(1));
 106     assert_eq!(x.or(None), Some(1));
 107
 108     let x: Option<isize> = None;
 109     assert_eq!(x.or(Some(2)), Some(2));
 110     assert_eq!(x.or(None), None);
 111 }
 112
 113 #[test]
 114 fn test_or_else() {
 115     let x: Option<isize> = Some(1);
 116     assert_eq!(x.or_else(|| Some(2)), Some(1));
 117     assert_eq!(x.or_else(|| None), Some(1));
 118
 119     let x: Option<isize> = None;
 120     assert_eq!(x.or_else(|| Some(2)), Some(2));
 121     assert_eq!(x.or_else(|| None), None);
 122 }
 123
 124 #[test]
 125 fn test_unwrap() {
 126     assert_eq!(Some(1).unwrap(), 1);
 127     let s = Some("hello".to_string()).unwrap();
 128     assert_eq!(s, "hello");
 129 }
 130
 131 #[test]
 132 #[should_panic]
 133 fn test_unwrap_panic1() {
 134     let x: Option<isize> = None;
 135     x.unwrap();
 136 }
 137
 138 #[test]
 139 #[should_panic]
 140 fn test_unwrap_panic2() {
 141     let x: Option<String> = None;
 142     x.unwrap();
 143 }
 144
 145 #[test]
 146 fn test_unwrap_or() {
 147     let x: Option<isize> = Some(1);
 148     assert_eq!(x.unwrap_or(2), 1);
 149
 150     let x: Option<isize> = None;
 151     assert_eq!(x.unwrap_or(2), 2);
 152 }
 153
 154 #[test]
 155 fn test_unwrap_or_else() {
 156     let x: Option<isize> = Some(1);
 157     assert_eq!(x.unwrap_or_else(|| 2), 1);
 158
 159     let x: Option<isize> = None;
 160     assert_eq!(x.unwrap_or_else(|| 2), 2);
 161 }
 162
 163 #[test]
 164 fn test_unwrap_unchecked() {
 165     assert_eq!(unsafe { Some(1).unwrap_unchecked() }, 1);
 166     let s = unsafe { Some("hello".to_string()).unwrap_unchecked() };
 167     assert_eq!(s, "hello");
 168 }
 169
 170 #[test]
 171 fn test_iter() {
 172     let val = 5;
 173
 174     let x = Some(val);
 175     let mut it = x.iter();
 176
 177     assert_eq!(it.size_hint(), (1, Some(1)));
 178     assert_eq!(it.next(), Some(&val));
 179     assert_eq!(it.size_hint(), (0, Some(0)));
 180     assert!(it.next().is_none());
 181
 182     let mut it = (&x).into_iter();
 183     assert_eq!(it.next(), Some(&val));
 184 }
 185
 186 #[test]
 187 fn test_mut_iter() {
 188     let mut val = 5;
 189     let new_val = 11;
 190
 191     let mut x = Some(val);
 192     {
 193         let mut it = x.iter_mut();
 194
 195         assert_eq!(it.size_hint(), (1, Some(1)));
 196
 197         match it.next() {
 198             Some(interior) => {
 199                 assert_eq!(*interior, val);
 200                 *interior = new_val;
 201             }
 202             None => assert!(false),
 203         }
 204
 205         assert_eq!(it.size_hint(), (0, Some(0)));
 206         assert!(it.next().is_none());
 207     }
 208     assert_eq!(x, Some(new_val));
 209
 210     let mut y = Some(val);
 211     let mut it = (&mut y).into_iter();
 212     assert_eq!(it.next(), Some(&mut val));
 213 }
 214
 215 #[test]
 216 fn test_ord() {
 217     let small = Some(1.0f64);
 218     let big = Some(5.0f64);
 219     let nan = Some(0.0f64 / 0.0);
 220     assert!(!(nan < big));
 221     assert!(!(nan > big));
 222     assert!(small < big);
 223     assert!(None < big);
 224     assert!(big > None);
 225 }
 226
 227 #[test]
 228 fn test_collect() {
 229     let v: Option<Vec<isize>> = (0..0).map(|_| Some(0)).collect();
 230     assert!(v == Some(vec![]));
 231
 232     let v: Option<Vec<isize>> = (0..3).map(|x| Some(x)).collect();
 233     assert!(v == Some(vec![0, 1, 2]));
 234
 235     let v: Option<Vec<isize>> = (0..3).map(|x| if x > 1 { None } else { Some(x) }).collect();
 236     assert!(v == None);
 237
 238     // test that it does not take more elements than it needs
 239     let mut functions: [Box<dyn Fn() -> Option<()>>; 3] =
 240         [box || Some(()), box || None, box || panic!()];
 241
 242     let v: Option<Vec<()>> = functions.iter_mut().map(|f| (*f)()).collect();
 243
 244     assert!(v == None);
 245 }
 246
 247 #[test]
 248 fn test_copied() {
 249     let val = 1;
 250     let val_ref = &val;
 251     let opt_none: Option<&'static u32> = None;
 252     let opt_ref = Some(&val);
 253     let opt_ref_ref = Some(&val_ref);
 254
 255     // None works
 256     assert_eq!(opt_none.clone(), None);
 257     assert_eq!(opt_none.copied(), None);
 258
 259     // Immutable ref works
 260     assert_eq!(opt_ref.clone(), Some(&val));
 261     assert_eq!(opt_ref.copied(), Some(1));
 262
 263     // Double Immutable ref works
 264     assert_eq!(opt_ref_ref.clone(), Some(&val_ref));
 265     assert_eq!(opt_ref_ref.clone().copied(), Some(&val));
 266     assert_eq!(opt_ref_ref.copied().copied(), Some(1));
 267 }
 268
 269 #[test]
 270 fn test_cloned() {
 271     let val = 1;
 272     let val_ref = &val;
 273     let opt_none: Option<&'static u32> = None;
 274     let opt_ref = Some(&val);
 275     let opt_ref_ref = Some(&val_ref);
 276
 277     // None works
 278     assert_eq!(opt_none.clone(), None);
 279     assert_eq!(opt_none.cloned(), None);
 280
 281     // Immutable ref works
 282     assert_eq!(opt_ref.clone(), Some(&val));
 283     assert_eq!(opt_ref.cloned(), Some(1));
 284
 285     // Double Immutable ref works
 286     assert_eq!(opt_ref_ref.clone(), Some(&val_ref));
 287     assert_eq!(opt_ref_ref.clone().cloned(), Some(&val));
 288     assert_eq!(opt_ref_ref.cloned().cloned(), Some(1));
 289 }
 290
 291 #[test]
 292 fn test_try() {
 293     fn try_option_some() -> Option<u8> {
 294         let val = Some(1)?;
 295         Some(val)
 296     }
 297     assert_eq!(try_option_some(), Some(1));
 298
 299     fn try_option_none() -> Option<u8> {
 300         let val = None?;
 301         Some(val)
 302     }
 303     assert_eq!(try_option_none(), None);
 304 }
 305
 306 #[test]
 307 fn test_option_as_deref() {
 308     // Some: &Option<T: Deref>::Some(T) -> Option<&T::Deref::Target>::Some(&*T)
 309     let ref_option = &Some(&42);
 310     assert_eq!(ref_option.as_deref(), Some(&42));
 311
 312     let ref_option = &Some(String::from("a result"));
 313     assert_eq!(ref_option.as_deref(), Some("a result"));
 314
 315     let ref_option = &Some(vec![1, 2, 3, 4, 5]);
 316     assert_eq!(ref_option.as_deref(), Some([1, 2, 3, 4, 5].as_slice()));
 317
 318     // None: &Option<T: Deref>>::None -> None
 319     let ref_option: &Option<&i32> = &None;
 320     assert_eq!(ref_option.as_deref(), None);
 321 }
 322
 323 #[test]
 324 fn test_option_as_deref_mut() {
 325     // Some: &mut Option<T: Deref>::Some(T) -> Option<&mut T::Deref::Target>::Some(&mut *T)
 326     let mut val = 42;
 327     let ref_option = &mut Some(&mut val);
 328     assert_eq!(ref_option.as_deref_mut(), Some(&mut 42));
 329
 330     let ref_option = &mut Some(String::from("a result"));
 331     assert_eq!(ref_option.as_deref_mut(), Some(String::from("a result").deref_mut()));
 332
 333     let ref_option = &mut Some(vec![1, 2, 3, 4, 5]);
 334     assert_eq!(ref_option.as_deref_mut(), Some([1, 2, 3, 4, 5].as_mut_slice()));
 335
 336     // None: &mut Option<T: Deref>>::None -> None
 337     let ref_option: &mut Option<&mut i32> = &mut None;
 338     assert_eq!(ref_option.as_deref_mut(), None);
 339 }
 340
 341 #[test]
 342 fn test_replace() {
 343     let mut x = Some(2);
 344     let old = x.replace(5);
 345
 346     assert_eq!(x, Some(5));
 347     assert_eq!(old, Some(2));
 348
 349     let mut x = None;
 350     let old = x.replace(3);
 351
 352     assert_eq!(x, Some(3));
 353     assert_eq!(old, None);
 354 }
 355
 356 #[test]
 357 fn option_const() {
 358     // test that the methods of `Option` are usable in a const context
 359
 360     const OPTION: Option<usize> = Some(32);
 361
 362     const REF: Option<&usize> = OPTION.as_ref();
 363     assert_eq!(REF, Some(&32));
 364
 365     const IS_SOME: bool = OPTION.is_some();
 366     assert!(IS_SOME);
 367
 368     const IS_NONE: bool = OPTION.is_none();
 369     assert!(!IS_NONE);
 370 }
 371
 372 #[test]
 373 fn test_unwrap_drop() {
 374     struct Dtor<'a> {
 375         x: &'a Cell<isize>,
 376     }
 377
 378     impl<'a> std::ops::Drop for Dtor<'a> {
 379         fn drop(&mut self) {
 380             self.x.set(self.x.get() - 1);
 381         }
 382     }
 383
 384     fn unwrap<T>(o: Option<T>) -> T {
 385         match o {
 386             Some(v) => v,
 387             None => panic!(),
 388         }
 389     }
 390
 391     let x = &Cell::new(1);
 392
 393     {
 394         let b = Some(Dtor { x });
 395         let _c = unwrap(b);
 396     }
 397
 398     assert_eq!(x.get(), 0);
 399 }
 400
 401 #[test]
 402 pub fn option_ext() {
 403     let thing = "{{ f }}";
 404     let f = thing.find("{{");
 405
 406     if f.is_none() {
 407         println!("None!");
 408     }
 409 }