basic test

Author: mustakimali

crates/ide-completion/src/completions/dot.rs

@@ -155,14 +155,20 @@ mod tests {
     use expect_test::{expect, Expect};
 
     use crate::tests::{
-        check_edit, completion_list_no_kw, completion_list_no_kw_with_private_editable,
+        check_edit, completion_list_exact_order, completion_list_no_kw,
+        completion_list_no_kw_with_private_editable,
     };
 
     fn check(ra_fixture: &str, expect: Expect) {
         let actual = completion_list_no_kw(ra_fixture);
         expect.assert_eq(&actual);
     }
 
+    fn check_exact_order(ra_fixture: &str, expect: Expect) {
+        let actual = completion_list_exact_order(ra_fixture);
+        expect.assert_eq(&actual);
+    }
+
     fn check_with_private_editable(ra_fixture: &str, expect: Expect) {
         let actual = completion_list_no_kw_with_private_editable(ra_fixture);
         expect.assert_eq(&actual);
@@ -265,6 +271,32 @@ fn foo(a: A) { a.$0() }
         );
     }
 
+    #[test]
+    fn test_usable_types_first() {
+        check_exact_order(
+            r#"
+struct A;
+impl A {
+    fn foo(&self) {}
+    fn new_1(input: u32) -> Self { A }
+    fn new_2() -> A { A }
+}
+
+fn test() {
+    let a = A::$0;
+}
+"#,
+            // preference:
+            // fn with no param that returns itself
+            // fn with param that returns itself
+            expect![[r#"
+                fn new_2()  fn() -> A
+                fn new_1(…) fn(u32) -> A
+                me foo(…)   fn(&self)
+            "#]],
+        );
+    }
+
     #[test]
     fn test_visibility_filtering() {
         check(

crates/ide-completion/src/tests.rs

@@ -88,6 +88,11 @@ pub(crate) fn completion_list_no_kw(ra_fixture: &str) -> String {
     completion_list_with_config(TEST_CONFIG, ra_fixture, false, None)
 }
 
+pub(crate) fn completion_list_exact_order(ra_fixture: &str) -> String {
+    let items = get_all_items(TEST_CONFIG, ra_fixture, None);
+    render_completion_list(items)
+}
+
 pub(crate) fn completion_list_no_kw_with_private_editable(ra_fixture: &str) -> String {
     let mut config = TEST_CONFIG;
     config.enable_private_editable = true;