diff --git a/test/css/strings.css b/test/css/strings.css
index 80e115c07..f2f45e829 100644
--- a/test/css/strings.css
+++ b/test/css/strings.css
@@ -38,3 +38,6 @@
   color: #0000ff;
   color: #ffa500;
 }
+.blood {
+  color: red;
+}
diff --git a/test/less/strings.less b/test/less/strings.less
index b6fd856ab..97d39dfe9 100644
--- a/test/less/strings.less
+++ b/test/less/strings.less
@@ -49,3 +49,9 @@
     .mix-mul(blue);
     .mix-mul(orange);
 }
+
+// selector interpolation
+@theme: blood;
+~".@{theme}" {
+  color: red;
+}