internal/rosa/gnu: test skip helper

The terribleness of GNU invites interesting helpers.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/gnu_test.go

@@ -0,0 +1,35 @@
+package rosa
+
+import (
+	"slices"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+func TestSkipGNUTests(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		tests []int
+		want  string
+	}{
+		{[]int{764}, "1-763 765-"},
+		{[]int{764, 0xcafe, 37, 9}, "1-8 10-36 38-763 765-51965 51967-"},
+		{[]int{1, 2, 0xbed}, "3-3052 3054-"},
+		{[]int{3, 4}, "1-2 5-"},
+	}
+	for _, tc := range testCases {
+		t.Run(strings.Join(slices.Collect(func(yield func(string) bool) {
+			for _, n := range tc.tests {
+				yield(strconv.Itoa(n))
+			}
+		}), ","), func(t *testing.T) {
+			t.Parallel()
+
+			if got := skipGNUTests(tc.tests...); got != tc.want {
+				t.Errorf("skipGNUTests: %q, want %q", got, tc.want)
+			}
+		})
+	}
+}