tests/mv: Test for particular edge cases when handling symlink files

tests/by-util/test_mv.rs

@@ -417,6 +417,54 @@ fn test_mv_same_hardlink() {
         .stderr_is(format!("mv: '{file_a}' and '{file_b}' are the same file\n",));
 }
 
+#[test]
+#[cfg(all(unix, not(target_os = "android")))]
+fn test_mv_same_symlink() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    let file_a = "test_mv_same_file_a";
+    let file_b = "test_mv_same_file_b";
+    let file_c = "test_mv_same_file_c";
+
+    at.touch(file_a);
+
+    at.symlink_file(file_a, file_b);
+
+    ucmd.arg(file_b)
+        .arg(file_a)
+        .fails()
+        .stderr_is(format!("mv: '{file_b}' and '{file_a}' are the same file\n",));
+
+    let (at2, mut ucmd2) = at_and_ucmd!();
+    at2.touch(file_a);
+
+    at2.symlink_file(file_a, file_b);
+    ucmd2.arg(file_a).arg(file_b).succeeds();
+    assert!(at2.file_exists(file_b));
+    assert!(!at2.file_exists(file_a));
+
+    let (at3, mut ucmd3) = at_and_ucmd!();
+    at3.touch(file_a);
+
+    at3.symlink_file(file_a, file_b);
+    at3.symlink_file(file_b, file_c);
+
+    ucmd3.arg(file_c).arg(file_b).succeeds();
+    assert!(!at3.symlink_exists(file_c));
+    assert!(at3.symlink_exists(file_b));
+
+    let (at4, mut ucmd4) = at_and_ucmd!();
+    at4.touch(file_a);
+
+    at4.symlink_file(file_a, file_b);
+    at4.symlink_file(file_b, file_c);
+
+    ucmd4
+        .arg(file_c)
+        .arg(file_a)
+        .fails()
+        .stderr_is(format!("mv: '{file_c}' and '{file_a}' are the same file\n",));
+}
+
 #[test]
 #[cfg(all(unix, not(target_os = "android")))]
 fn test_mv_same_hardlink_backup_simple() {