features: add tests

internal/feature/testing_test.go

@@ -0,0 +1,19 @@
+package feature_test
+
+import (
+	"testing"
+
+	"github.com/restic/restic/internal/feature"
+	rtest "github.com/restic/restic/internal/test"
+)
+
+func TestSetFeatureFlag(t *testing.T) {
+	flags := buildTestFlagSet()
+	rtest.Assert(t, !flags.Enabled(alpha), "expected alpha feature to be disabled")
+
+	restore := feature.TestSetFlag(t, flags, alpha, true)
+	rtest.Assert(t, flags.Enabled(alpha), "expected alpha feature to be enabled")
+
+	restore()
+	rtest.Assert(t, !flags.Enabled(alpha), "expected alpha feature to be disabled again")
+}