util: Rename SortedStrSliceCompare and move to util package

util/util.go

@@ -19,6 +19,7 @@
 package util
 
 import (
+	"fmt"
 	"path"
 	"sort"
 	"strings"
@@ -376,3 +377,27 @@ func SystemBusPrivateUsable() (conn *dbus.Conn, err error) {
 	}
 	return conn, nil // success
 }
+
+// SortedStrSliceCompare takes two lists of strings and returns whether or not
+// they are equivalent. It will return nil if both sets contain the same
+// elements, regardless of order, and an error if they do not.
+func SortedStrSliceCompare(a, b []string) error {
+	if len(a) != len(b) {
+		return fmt.Errorf("slices have different lengths: %d vs %d", len(a), len(b))
+	}
+
+	// make a copy of each to sort, so we don't reorder the inputs
+	x := make([]string, len(a))
+	y := make([]string, len(b))
+	copy(x, a)
+	copy(y, b)
+
+	sort.Strings(x)
+	sort.Strings(y)
+	for i := range x {
+		if x[i] != y[i] {
+			return fmt.Errorf("values do not match: %s vs %s", x[i], y[i])
+		}
+	}
+	return nil
+}

util/util_test.go

@@ -813,3 +813,45 @@ func TestUtilFlattenListWithSplit1(t *testing.T) {
 		}
 	}
 }
+
+func TestSortedStrSliceCompare0(t *testing.T) {
+	slice0 := []string{"foo", "bar", "baz"}
+	slice1 := []string{"bar", "foo", "baz"}
+
+	if err := SortedStrSliceCompare(slice0, slice1); err != nil {
+		t.Errorf("slices were not evaluated as equivalent: %v, %v", slice0, slice1)
+	}
+}
+
+func TestSortedStrSliceCompare1(t *testing.T) {
+	slice0 := []string{"foo", "bar", "baz"}
+	slice1 := []string{"fi", "fi", "fo"}
+
+	if err := SortedStrSliceCompare(slice0, slice1); err == nil {
+		t.Errorf("slices were evaluated as equivalent: %v, %v", slice0, slice1)
+	}
+}
+
+func TestSortedStrSliceCompare2(t *testing.T) {
+	slice0 := []string{"foo", "bar", "baz"}
+	slice1 := []string{"foo", "bar"}
+
+	if err := SortedStrSliceCompare(slice0, slice1); err == nil {
+		t.Errorf("slices were evaluated as equivalent: %v, %v", slice0, slice1)
+	}
+}
+
+func TestSortedStrSliceCompare3(t *testing.T) {
+	slice0 := []string{"foo", "bar", "baz"}
+	slice1 := []string{"zip", "zap", "zop"}
+
+	_ = SortedStrSliceCompare(slice0, slice1)
+
+	if slice0[0] != "foo" || slice0[1] != "bar" || slice0[2] != "baz" {
+		t.Errorf("input slice reordered to: %v", slice0)
+	}
+
+	if slice1[0] != "zip" || slice1[1] != "zap" || slice1[2] != "zop" {
+		t.Errorf("input slice reordered to: %v", slice1)
+	}
+}