library/core/tests/option.rs

   1 use core::array::FixedSizeArray;
   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_iter() {
 165     let val = 5;
 166
 167     let x = Some(val);
 168     let mut it = x.iter();
 169
 170     assert_eq!(it.size_hint(), (1, Some(1)));
 171     assert_eq!(it.next(), Some(&val));
 172     assert_eq!(it.size_hint(), (0, Some(0)));
 173     assert!(it.next().is_none());
 174
 175     let mut it = (&x).into_iter();
 176     assert_eq!(it.next(), Some(&val));
 177 }
 178
 179 #[test]
 180 fn test_mut_iter() {
 181     let mut val = 5;
 182     let new_val = 11;
 183
 184     let mut x = Some(val);
 185     {
 186         let mut it = x.iter_mut();
 187
 188         assert_eq!(it.size_hint(), (1, Some(1)));
 189
 190         match it.next() {
 191             Some(interior) => {
 192                 assert_eq!(*interior, val);
 193                 *interior = new_val;
 194             }
 195             None => assert!(false),
 196         }
 197
 198         assert_eq!(it.size_hint(), (0, Some(0)));
 199         assert!(it.next().is_none());
 200     }
 201     assert_eq!(x, Some(new_val));
 202
 203     let mut y = Some(val);
 204     let mut it = (&mut y).into_iter();
 205     assert_eq!(it.next(), Some(&mut val));
 206 }
 207
 208 #[test]
 209 fn test_ord() {
 210     let small = Some(1.0f64);
 211     let big = Some(5.0f64);
 212     let nan = Some(0.0f64 / 0.0);
 213     assert!(!(nan < big));
 214     assert!(!(nan > big));
 215     assert!(small < big);
 216     assert!(None < big);
 217     assert!(big > None);
 218 }
 219
 220 #[test]
 221 fn test_collect() {
 222     let v: Option<Vec<isize>> = (0..0).map(|_| Some(0)).collect();
 223     assert!(v == Some(vec![]));
 224
 225     let v: Option<Vec<isize>> = (0..3).map(|x| Some(x)).collect();
 226     assert!(v == Some(vec![0, 1, 2]));
 227
 228     let v: Option<Vec<isize>> = (0..3).map(|x| if x > 1 { None } else { Some(x) }).collect();
 229     assert!(v == None);
 230
 231     // test that it does not take more elements than it needs
 232     let mut functions: [Box<dyn Fn() -> Option<()>>; 3] =
 233         [box || Some(()), box || None, box || panic!()];
 234
 235     let v: Option<Vec<()>> = functions.iter_mut().map(|f| (*f)()).collect();
 236
 237     assert!(v == None);
 238 }
 239
 240 #[test]
 241 fn test_copied() {
 242     let val = 1;
 243     let val_ref = &val;
 244     let opt_none: Option<&'static u32> = None;
 245     let opt_ref = Some(&val);
 246     let opt_ref_ref = Some(&val_ref);
 247
 248     // None works
 249     assert_eq!(opt_none.clone(), None);
 250     assert_eq!(opt_none.copied(), None);
 251
 252     // Immutable ref works
 253     assert_eq!(opt_ref.clone(), Some(&val));
 254     assert_eq!(opt_ref.copied(), Some(1));
 255
 256     // Double Immutable ref works
 257     assert_eq!(opt_ref_ref.clone(), Some(&val_ref));
 258     assert_eq!(opt_ref_ref.clone().copied(), Some(&val));
 259     assert_eq!(opt_ref_ref.copied().copied(), Some(1));
 260 }
 261
 262 #[test]
 263 fn test_cloned() {
 264     let val = 1;
 265     let val_ref = &val;
 266     let opt_none: Option<&'static u32> = None;
 267     let opt_ref = Some(&val);
 268     let opt_ref_ref = Some(&val_ref);
 269
 270     // None works
 271     assert_eq!(opt_none.clone(), None);
 272     assert_eq!(opt_none.cloned(), None);
 273
 274     // Immutable ref works
 275     assert_eq!(opt_ref.clone(), Some(&val));
 276     assert_eq!(opt_ref.cloned(), Some(1));
 277
 278     // Double Immutable ref works
 279     assert_eq!(opt_ref_ref.clone(), Some(&val_ref));
 280     assert_eq!(opt_ref_ref.clone().cloned(), Some(&val));
 281     assert_eq!(opt_ref_ref.cloned().cloned(), Some(1));
 282 }
 283
 284 #[test]
 285 fn test_try() {
 286     fn try_option_some() -> Option<u8> {
 287         let val = Some(1)?;
 288         Some(val)
 289     }
 290     assert_eq!(try_option_some(), Some(1));
 291
 292     fn try_option_none() -> Option<u8> {
 293         let val = None?;
 294         Some(val)
 295     }
 296     assert_eq!(try_option_none(), None);
 297
 298     fn try_option_ok() -> Result<u8, NoneError> {
 299         let val = Some(1)?;
 300         Ok(val)
 301     }
 302     assert_eq!(try_option_ok(), Ok(1));
 303
 304     fn try_option_err() -> Result<u8, NoneError> {
 305         let val = None?;
 306         Ok(val)
 307     }
 308     assert_eq!(try_option_err(), Err(NoneError));
 309 }
 310
 311 #[test]
 312 fn test_option_as_deref() {
 313     // Some: &Option<T: Deref>::Some(T) -> Option<&T::Deref::Target>::Some(&*T)
 314     let ref_option = &Some(&42);
 315     assert_eq!(ref_option.as_deref(), Some(&42));
 316
 317     let ref_option = &Some(String::from("a result"));
 318     assert_eq!(ref_option.as_deref(), Some("a result"));
 319
 320     let ref_option = &Some(vec![1, 2, 3, 4, 5]);
 321     assert_eq!(ref_option.as_deref(), Some([1, 2, 3, 4, 5].as_slice()));
 322
 323     // None: &Option<T: Deref>>::None -> None
 324     let ref_option: &Option<&i32> = &None;
 325     assert_eq!(ref_option.as_deref(), None);
 326 }
 327
 328 #[test]
 329 fn test_option_as_deref_mut() {
 330     // Some: &mut Option<T: Deref>::Some(T) -> Option<&mut T::Deref::Target>::Some(&mut *T)
 331     let mut val = 42;
 332     let ref_option = &mut Some(&mut val);
 333     assert_eq!(ref_option.as_deref_mut(), Some(&mut 42));
 334
 335     let ref_option = &mut Some(String::from("a result"));
 336     assert_eq!(ref_option.as_deref_mut(), Some(String::from("a result").deref_mut()));
 337
 338     let ref_option = &mut Some(vec![1, 2, 3, 4, 5]);
 339     assert_eq!(ref_option.as_deref_mut(), Some([1, 2, 3, 4, 5].as_mut_slice()));
 340
 341     // None: &mut Option<T: Deref>>::None -> None
 342     let ref_option: &mut Option<&mut i32> = &mut None;
 343     assert_eq!(ref_option.as_deref_mut(), None);
 344 }
 345
 346 #[test]
 347 fn test_replace() {
 348     let mut x = Some(2);
 349     let old = x.replace(5);
 350
 351     assert_eq!(x, Some(5));
 352     assert_eq!(old, Some(2));
 353
 354     let mut x = None;
 355     let old = x.replace(3);
 356
 357     assert_eq!(x, Some(3));
 358     assert_eq!(old, None);
 359 }