Add str::[r]split_once

This is useful for quick&dirty parsing of key: value config pairs

2 files changed, 25 insertions, 0 deletions

diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index e2dc816b015..fa20a466715 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -6,6 +6,7 @@
 #![feature(map_first_last)]
 #![feature(new_uninit)]
 #![feature(pattern)]
+#![feature(str_split_once)]
 #![feature(trusted_len)]
 #![feature(try_reserve)]
 #![feature(unboxed_closures)]
diff --git a/library/alloc/tests/str.rs b/library/alloc/tests/str.rs
index eee98d45340..b20cf076aca 100644
--- a/library/alloc/tests/str.rs
+++ b/library/alloc/tests/str.rs
@@ -1319,6 +1319,30 @@ fn test_rsplitn() {
 }
 
 #[test]
+fn test_split_once() {
+    assert_eq!("".split_once("->"), None);
+    assert_eq!("-".split_once("->"), None);
+    assert_eq!("->".split_once("->"), Some(("", "")));
+    assert_eq!("a->".split_once("->"), Some(("a", "")));
+    assert_eq!("->b".split_once("->"), Some(("", "b")));
+    assert_eq!("a->b".split_once("->"), Some(("a", "b")));
+    assert_eq!("a->b->c".split_once("->"), Some(("a", "b->c")));
+    assert_eq!("---".split_once("--"), Some(("", "-")));
+}
+
+#[test]
+fn test_rsplit_once() {
+    assert_eq!("".rsplit_once("->"), None);
+    assert_eq!("-".rsplit_once("->"), None);
+    assert_eq!("->".rsplit_once("->"), Some(("", "")));
+    assert_eq!("a->".rsplit_once("->"), Some(("a", "")));
+    assert_eq!("->b".rsplit_once("->"), Some(("", "b")));
+    assert_eq!("a->b".rsplit_once("->"), Some(("a", "b")));
+    assert_eq!("a->b->c".rsplit_once("->"), Some(("a->b", "c")));
+    assert_eq!("---".rsplit_once("--"), Some(("-", "")));
+}
+
+#[test]
 fn test_split_whitespace() {
     let data = "\n \tMäry   häd\tä  little lämb\nLittle lämb\n";
     let words: Vec<&str> = data.split_whitespace().collect();