1 files changed, 23 insertions, 0 deletions
diff --git a/compiler/rustc_data_structures/src/binary_search_util/tests.rs b/compiler/rustc_data_structures/src/binary_search_util/tests.rs
new file mode 100644
index 000000000..d74febb5c
--- /dev/null
+++ b/compiler/rustc_data_structures/src/binary_search_util/tests.rs
@@ -0,0 +1,23 @@
+use super::*;
+
+type Element = (usize, &'static str);
+
+fn test_map() -> Vec<Element> {
+    let mut data = vec![(3, "three-a"), (0, "zero"), (3, "three-b"), (22, "twenty-two")];
+    data.sort_by_key(get_key);
+    data
+}
+
+fn get_key(data: &Element) -> usize {
+    data.0
+}
+
+#[test]
+fn binary_search_slice_test() {
+    let map = test_map();
+    assert_eq!(binary_search_slice(&map, get_key, &0), &[(0, "zero")]);
+    assert_eq!(binary_search_slice(&map, get_key, &1), &[]);
+    assert_eq!(binary_search_slice(&map, get_key, &3), &[(3, "three-a"), (3, "three-b")]);
+    assert_eq!(binary_search_slice(&map, get_key, &22), &[(22, "twenty-two")]);
+    assert_eq!(binary_search_slice(&map, get_key, &23), &[]);
+}