1 files changed, 50 insertions, 0 deletions
diff --git a/src/librustdoc/html/tests.rs b/src/librustdoc/html/tests.rs
new file mode 100644
index 000000000..437d3995e
--- /dev/null
+++ b/src/librustdoc/html/tests.rs
@@ -0,0 +1,50 @@
+use crate::html::format::href_relative_parts;
+use rustc_span::{sym, Symbol};
+
+fn assert_relative_path(expected: &[Symbol], relative_to_fqp: &[Symbol], fqp: &[Symbol]) {
+    // No `create_default_session_globals_then` call is needed here because all
+    // the symbols used are static, and no `Symbol::intern` calls occur.
+    assert_eq!(expected, href_relative_parts(&fqp, &relative_to_fqp).collect::<Vec<_>>());
+}
+
+#[test]
+fn href_relative_parts_basic() {
+    let relative_to_fqp = &[sym::std, sym::vec];
+    let fqp = &[sym::std, sym::iter];
+    assert_relative_path(&[sym::dotdot, sym::iter], relative_to_fqp, fqp);
+}
+
+#[test]
+fn href_relative_parts_parent_module() {
+    let relative_to_fqp = &[sym::std, sym::vec];
+    let fqp = &[sym::std];
+    assert_relative_path(&[sym::dotdot], relative_to_fqp, fqp);
+}
+
+#[test]
+fn href_relative_parts_different_crate() {
+    let relative_to_fqp = &[sym::std, sym::vec];
+    let fqp = &[sym::core, sym::iter];
+    assert_relative_path(&[sym::dotdot, sym::dotdot, sym::core, sym::iter], relative_to_fqp, fqp);
+}
+
+#[test]
+fn href_relative_parts_same_module() {
+    let relative_to_fqp = &[sym::std, sym::vec];
+    let fqp = &[sym::std, sym::vec];
+    assert_relative_path(&[], relative_to_fqp, fqp);
+}
+
+#[test]
+fn href_relative_parts_child_module() {
+    let relative_to_fqp = &[sym::std];
+    let fqp = &[sym::std, sym::vec];
+    assert_relative_path(&[sym::vec], relative_to_fqp, fqp);
+}
+
+#[test]
+fn href_relative_parts_root() {
+    let relative_to_fqp = &[];
+    let fqp = &[sym::std];
+    assert_relative_path(&[sym::std], relative_to_fqp, fqp);
+}