Move join_lines to ra_ide_api

crates/ra_ide_api/src/test_utils.rs

@@ -0,0 +1,24 @@
+use ra_syntax::{SourceFile, TextUnit};
+
+use crate::LocalEdit;
+pub use test_utils::*;
+
+pub fn check_action<F: Fn(&SourceFile, TextUnit) -> Option<LocalEdit>>(
+    before: &str,
+    after: &str,
+    f: F,
+) {
+    let (before_cursor_pos, before) = extract_offset(before);
+    let file = SourceFile::parse(&before);
+    let result = f(&file, before_cursor_pos).expect("code action is not applicable");
+    let actual = result.edit.apply(&before);
+    let actual_cursor_pos = match result.cursor_position {
+        None => result
+            .edit
+            .apply_to_offset(before_cursor_pos)
+            .expect("cursor position is affected by the edit"),
+        Some(off) => off,
+    };
+    let actual = add_cursor(&actual, actual_cursor_pos);
+    assert_eq_text!(after, &actual);
+}