1 files changed, 23 insertions, 0 deletions
diff --git a/cmd/krino/sort_test.go b/cmd/krino/sort_test.go
new file mode 100644
index 0000000..a646503
--- /dev/null
+++ b/cmd/krino/sort_test.go
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package main
+
+import "testing"
+
+// TestRelWidthAndPadCellCountRunes: C4. relWidth and padCell must measure
+// column width in runes, not bytes, or a name carrying diacritics
+// misaligns its column - "próba.txt" is 9 runes but 10 bytes (ó is a
+// two-byte UTF-8 sequence), one column narrower than its byte length
+// would suggest.
+func TestRelWidthAndPadCellCountRunes(t *testing.T) {
+	rels := []string{"a.txt", "próba.txt"}
+	if w := relWidth(rels); w != 9 {
+		t.Fatalf("relWidth(%q) = %d, want 9 (rune count of próba.txt, not its %d bytes)", rels, w, len("próba.txt"))
+	}
+	if got, want := padCell("a.txt", 9), "a.txt    "; got != want {
+		t.Fatalf("padCell(%q, 9) = %q, want %q", "a.txt", got, want)
+	}
+	if got, want := padCell("próba.txt", 9), "próba.txt"; got != want {
+		t.Fatalf("padCell(%q, 9) = %q, want %q (already at width: no padding)", "próba.txt", got, want)
+	}
+}