tests: Implement a function.

We don't actually call the function, but it avoids an inspection
warning from Jetbrains CLion, and doesn't seem unreasonable.

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/test_size.cc b/tests/test_size.cc
index d49af99..cf94a8b 100644
--- a/tests/test_size.cc
+++ b/tests/test_size.cc
@@ -15,7 +15,7 @@ namespace
 {
 struct A
 {
-  void foo();
+  void foo() {}
 };
 } // end anonymous namespace