Index: unittests/Support/Path.cpp
===================================================================
--- unittests/Support/Path.cpp
+++ unittests/Support/Path.cpp
@@ -543,11 +543,11 @@
     fs::expand_tilde("~", Actual);
     EXPECT_EQ(Expected, Actual);
 
-    path::append(Expected, "foo");
-
 #ifdef _WIN32
+    Expected += "\\foo";
     fs::expand_tilde("~\\foo", Actual);
 #else
+    Expected += "/foo";
     fs::expand_tilde("~/foo", Actual);
 #endif