rust/library/core/tests/option.rs

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use core::cell::Cell;
use core::clone::Clone;
use core::mem;
use core::ops::DerefMut;
use core::option::*;
#[test]
fn test_get_ptr() {
unsafe {
let x: Box<_> = Box::new(0);
let addr_x: *const isize = mem::transmute(&*x);
let opt = Some(x);
let y = opt.unwrap();
let addr_y: *const isize = mem::transmute(&*y);
assert_eq!(addr_x, addr_y);
}
}
#[test]
fn test_get_str() {
let x = "test".to_string();
let addr_x = x.as_ptr();
let opt = Some(x);
let y = opt.unwrap();
let addr_y = y.as_ptr();
assert_eq!(addr_x, addr_y);
}
#[test]
fn test_get_resource() {
use core::cell::RefCell;
use std::rc::Rc;
struct R {
i: Rc<RefCell<isize>>,
}
impl Drop for R {
fn drop(&mut self) {
let ii = &*self.i;
let i = *ii.borrow();
*ii.borrow_mut() = i + 1;
}
}
fn r(i: Rc<RefCell<isize>>) -> R {
R { i }
}
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let i = Rc::new(RefCell::new(0));
{
let x = r(i.clone());
let opt = Some(x);
let _y = opt.unwrap();
}
assert_eq!(*i.borrow(), 1);
}
#[test]
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#[allow(for_loops_over_fallibles)]
fn test_option_dance() {
let x = Some(());
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let mut y = Some(5);
let mut y2 = 0;
for _x in x {
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y2 = y.take().unwrap();
}
assert_eq!(y2, 5);
assert!(y.is_none());
}
#[test]
#[should_panic]
fn test_option_too_much_dance() {
struct A;
let mut y = Some(A);
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let _y2 = y.take().unwrap();
let _y3 = y.take().unwrap();
}
#[test]
fn test_and() {
let x: Option<isize> = Some(1);
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assert_eq!(x.and(Some(2)), Some(2));
assert_eq!(x.and(None::<isize>), None);
let x: Option<isize> = None;
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assert_eq!(x.and(Some(2)), None);
assert_eq!(x.and(None::<isize>), None);
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const FOO: Option<isize> = Some(1);
const A: Option<isize> = FOO.and(Some(2));
const B: Option<isize> = FOO.and(None);
assert_eq!(A, Some(2));
assert_eq!(B, None);
const BAR: Option<isize> = None;
const C: Option<isize> = BAR.and(Some(2));
const D: Option<isize> = BAR.and(None);
assert_eq!(C, None);
assert_eq!(D, None);
}
#[test]
fn test_and_then() {
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const fn plus_one(x: isize) -> Option<isize> {
Some(x + 1)
}
const fn none(_: isize) -> Option<isize> {
None
}
let x: Option<isize> = Some(1);
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assert_eq!(x.and_then(plus_one), Some(2));
assert_eq!(x.and_then(none), None);
let x: Option<isize> = None;
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assert_eq!(x.and_then(plus_one), None);
assert_eq!(x.and_then(none), None);
const FOO: Option<isize> = Some(1);
const A: Option<isize> = FOO.and_then(plus_one);
const B: Option<isize> = FOO.and_then(none);
assert_eq!(A, Some(2));
assert_eq!(B, None);
const BAR: Option<isize> = None;
const C: Option<isize> = BAR.and_then(plus_one);
const D: Option<isize> = BAR.and_then(none);
assert_eq!(C, None);
assert_eq!(D, None);
}
#[test]
fn test_or() {
let x: Option<isize> = Some(1);
assert_eq!(x.or(Some(2)), Some(1));
assert_eq!(x.or(None), Some(1));
let x: Option<isize> = None;
assert_eq!(x.or(Some(2)), Some(2));
assert_eq!(x.or(None), None);
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const FOO: Option<isize> = Some(1);
const A: Option<isize> = FOO.or(Some(2));
const B: Option<isize> = FOO.or(None);
assert_eq!(A, Some(1));
assert_eq!(B, Some(1));
const BAR: Option<isize> = None;
const C: Option<isize> = BAR.or(Some(2));
const D: Option<isize> = BAR.or(None);
assert_eq!(C, Some(2));
assert_eq!(D, None);
}
#[test]
fn test_or_else() {
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const fn two() -> Option<isize> {
Some(2)
}
const fn none() -> Option<isize> {
None
}
let x: Option<isize> = Some(1);
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assert_eq!(x.or_else(two), Some(1));
assert_eq!(x.or_else(none), Some(1));
let x: Option<isize> = None;
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assert_eq!(x.or_else(two), Some(2));
assert_eq!(x.or_else(none), None);
const FOO: Option<isize> = Some(1);
const A: Option<isize> = FOO.or_else(two);
const B: Option<isize> = FOO.or_else(none);
assert_eq!(A, Some(1));
assert_eq!(B, Some(1));
const BAR: Option<isize> = None;
const C: Option<isize> = BAR.or_else(two);
const D: Option<isize> = BAR.or_else(none);
assert_eq!(C, Some(2));
assert_eq!(D, None);
}
#[test]
fn test_unwrap() {
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assert_eq!(Some(1).unwrap(), 1);
let s = Some("hello".to_string()).unwrap();
assert_eq!(s, "hello");
}
#[test]
#[should_panic]
fn test_unwrap_panic1() {
let x: Option<isize> = None;
x.unwrap();
}
#[test]
#[should_panic]
fn test_unwrap_panic2() {
let x: Option<String> = None;
x.unwrap();
}
#[test]
fn test_unwrap_or() {
let x: Option<isize> = Some(1);
assert_eq!(x.unwrap_or(2), 1);
let x: Option<isize> = None;
assert_eq!(x.unwrap_or(2), 2);
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const A: isize = Some(1).unwrap_or(2);
const B: isize = None.unwrap_or(2);
assert_eq!(A, 1);
assert_eq!(B, 2);
}
#[test]
fn test_unwrap_or_else() {
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const fn two() -> isize {
2
}
let x: Option<isize> = Some(1);
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assert_eq!(x.unwrap_or_else(two), 1);
let x: Option<isize> = None;
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assert_eq!(x.unwrap_or_else(two), 2);
const A: isize = Some(1).unwrap_or_else(two);
const B: isize = None.unwrap_or_else(two);
assert_eq!(A, 1);
assert_eq!(B, 2);
}
#[test]
fn test_unwrap_unchecked() {
assert_eq!(unsafe { Some(1).unwrap_unchecked() }, 1);
let s = unsafe { Some("hello".to_string()).unwrap_unchecked() };
assert_eq!(s, "hello");
}
#[test]
fn test_iter() {
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let val = 5;
let x = Some(val);
let mut it = x.iter();
assert_eq!(it.size_hint(), (1, Some(1)));
assert_eq!(it.next(), Some(&val));
assert_eq!(it.size_hint(), (0, Some(0)));
assert!(it.next().is_none());
let mut it = (&x).into_iter();
assert_eq!(it.next(), Some(&val));
}
#[test]
fn test_mut_iter() {
let mut val = 5;
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let new_val = 11;
let mut x = Some(val);
{
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let mut it = x.iter_mut();
assert_eq!(it.size_hint(), (1, Some(1)));
match it.next() {
Some(interior) => {
assert_eq!(*interior, val);
*interior = new_val;
}
None => assert!(false),
}
assert_eq!(it.size_hint(), (0, Some(0)));
assert!(it.next().is_none());
}
assert_eq!(x, Some(new_val));
let mut y = Some(val);
let mut it = (&mut y).into_iter();
assert_eq!(it.next(), Some(&mut val));
}
#[test]
fn test_ord() {
let small = Some(1.0f64);
let big = Some(5.0f64);
let nan = Some(0.0f64 / 0.0);
assert!(!(nan < big));
assert!(!(nan > big));
assert!(small < big);
assert!(None < big);
assert!(big > None);
}
#[test]
fn test_collect() {
let v: Option<Vec<isize>> = (0..0).map(|_| Some(0)).collect();
assert!(v == Some(vec![]));
let v: Option<Vec<isize>> = (0..3).map(|x| Some(x)).collect();
assert!(v == Some(vec![0, 1, 2]));
let v: Option<Vec<isize>> = (0..3).map(|x| if x > 1 { None } else { Some(x) }).collect();
assert!(v == None);
// test that it does not take more elements than it needs
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let mut functions: [Box<dyn Fn() -> Option<()>>; 3] =
[Box::new(|| Some(())), Box::new(|| None), Box::new(|| panic!())];
let v: Option<Vec<()>> = functions.iter_mut().map(|f| (*f)()).collect();
assert!(v == None);
}
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#[test]
fn test_copied() {
let val = 1;
let val_ref = &val;
let opt_none: Option<&'static u32> = None;
let opt_ref = Some(&val);
let opt_ref_ref = Some(&val_ref);
// None works
assert_eq!(opt_none.clone(), None);
assert_eq!(opt_none.copied(), None);
// Immutable ref works
assert_eq!(opt_ref.clone(), Some(&val));
assert_eq!(opt_ref.copied(), Some(1));
// Double Immutable ref works
assert_eq!(opt_ref_ref.clone(), Some(&val_ref));
assert_eq!(opt_ref_ref.clone().copied(), Some(&val));
assert_eq!(opt_ref_ref.copied().copied(), Some(1));
}
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#[test]
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fn test_cloned() {
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let val = 1;
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let val_ref = &val;
let opt_none: Option<&'static u32> = None;
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let opt_ref = Some(&val);
let opt_ref_ref = Some(&val_ref);
// None works
assert_eq!(opt_none.clone(), None);
assert_eq!(opt_none.cloned(), None);
// Immutable ref works
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assert_eq!(opt_ref.clone(), Some(&val));
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assert_eq!(opt_ref.cloned(), Some(1));
// Double Immutable ref works
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assert_eq!(opt_ref_ref.clone(), Some(&val_ref));
assert_eq!(opt_ref_ref.clone().cloned(), Some(&val));
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assert_eq!(opt_ref_ref.cloned().cloned(), Some(1));
}
#[test]
fn test_try() {
fn try_option_some() -> Option<u8> {
let val = Some(1)?;
Some(val)
}
assert_eq!(try_option_some(), Some(1));
fn try_option_none() -> Option<u8> {
let val = None?;
Some(val)
}
assert_eq!(try_option_none(), None);
}
#[test]
fn test_option_as_deref() {
// Some: &Option<T: Deref>::Some(T) -> Option<&T::Deref::Target>::Some(&*T)
let ref_option = &Some(&42);
assert_eq!(ref_option.as_deref(), Some(&42));
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let ref_option = &Some(String::from("a result"));
assert_eq!(ref_option.as_deref(), Some("a result"));
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let ref_option = &Some(vec![1, 2, 3, 4, 5]);
assert_eq!(ref_option.as_deref(), Some([1, 2, 3, 4, 5].as_slice()));
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// None: &Option<T: Deref>>::None -> None
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let ref_option: &Option<&i32> = &None;
assert_eq!(ref_option.as_deref(), None);
}
#[test]
fn test_option_as_deref_mut() {
// Some: &mut Option<T: Deref>::Some(T) -> Option<&mut T::Deref::Target>::Some(&mut *T)
let mut val = 42;
let ref_option = &mut Some(&mut val);
assert_eq!(ref_option.as_deref_mut(), Some(&mut 42));
let ref_option = &mut Some(String::from("a result"));
assert_eq!(ref_option.as_deref_mut(), Some(String::from("a result").deref_mut()));
let ref_option = &mut Some(vec![1, 2, 3, 4, 5]);
assert_eq!(ref_option.as_deref_mut(), Some([1, 2, 3, 4, 5].as_mut_slice()));
// None: &mut Option<T: Deref>>::None -> None
let ref_option: &mut Option<&mut i32> = &mut None;
assert_eq!(ref_option.as_deref_mut(), None);
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}
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#[test]
fn test_replace() {
let mut x = Some(2);
let old = x.replace(5);
assert_eq!(x, Some(5));
assert_eq!(old, Some(2));
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let mut x = None;
let old = x.replace(3);
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assert_eq!(x, Some(3));
assert_eq!(old, None);
}
#[test]
fn option_const() {
// test that the methods of `Option` are usable in a const context
const OPTION: Option<usize> = Some(32);
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assert_eq!(OPTION, Some(32));
const OPTION_FROM: Option<usize> = Option::from(32);
assert_eq!(OPTION_FROM, Some(32));
const REF: Option<&usize> = OPTION.as_ref();
assert_eq!(REF, Some(&32));
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const REF_FROM: Option<&usize> = Option::from(&OPTION);
assert_eq!(REF_FROM, Some(&32));
const IS_SOME: bool = OPTION.is_some();
assert!(IS_SOME);
const IS_NONE: bool = OPTION.is_none();
assert!(!IS_NONE);
const COPIED: Option<usize> = OPTION.as_ref().copied();
assert_eq!(COPIED, OPTION);
}
#[test]
const fn option_const_mut() {
// test that the methods of `Option` that take mutable references are usable in a const context
let mut option: Option<usize> = Some(32);
let _take = option.take();
let _replace = option.replace(42);
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{
let as_mut = option.as_mut();
match as_mut {
Some(v) => *v = 32,
None => unreachable!(),
}
}
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{
let as_mut: Option<&mut usize> = Option::from(&mut option);
match as_mut {
Some(v) => *v = 42,
None => unreachable!(),
}
}
}
#[test]
fn test_unwrap_drop() {
struct Dtor<'a> {
x: &'a Cell<isize>,
}
impl<'a> std::ops::Drop for Dtor<'a> {
fn drop(&mut self) {
self.x.set(self.x.get() - 1);
}
}
fn unwrap<T>(o: Option<T>) -> T {
match o {
Some(v) => v,
None => panic!(),
}
}
let x = &Cell::new(1);
{
let b = Some(Dtor { x });
let _c = unwrap(b);
}
assert_eq!(x.get(), 0);
}
#[test]
fn option_ext() {
let thing = "{{ f }}";
let f = thing.find("{{");
if f.is_none() {
println!("None!");
}
}
#[test]
fn zip_options() {
let x = Some(10);
let y = Some("foo");
let z: Option<usize> = None;
assert_eq!(x.zip(y), Some((10, "foo")));
assert_eq!(x.zip(z), None);
assert_eq!(z.zip(x), None);
}
#[test]
fn unzip_options() {
let x = Some((10, "foo"));
let y = None::<(bool, i32)>;
assert_eq!(x.unzip(), (Some(10), Some("foo")));
assert_eq!(y.unzip(), (None, None));
}
#[test]
fn zip_unzip_roundtrip() {
let x = Some(10);
let y = Some("foo");
let z = x.zip(y);
assert_eq!(z, Some((10, "foo")));
let a = z.unzip();
assert_eq!(a, (x, y));
}