From 1d991b79ccd64556f945e57db5f9009ecf3d590c Mon Sep 17 00:00:00 2001
From: Chip Hogg <chogg@aurora.tech>
Date: Fri, 15 Dec 2023 11:50:33 -0500
Subject: [PATCH] Print unit labels if test fails

---
 au/quantity_test.cc | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/au/quantity_test.cc b/au/quantity_test.cc
index 2c51bd5a..553ce3eb 100644
--- a/au/quantity_test.cc
+++ b/au/quantity_test.cc
@@ -33,10 +33,16 @@ constexpr auto miles = QuantityMaker<Miles>{};
 struct Inches : decltype(Feet{} / mag<12>()) {};
 constexpr auto inches = QuantityMaker<Inches>{};
 
-struct Yards : decltype(Feet{} * mag<3>()) {};
+struct Yards : decltype(Feet{} * mag<3>()) {
+    static constexpr const char label[] = "yd";
+};
+constexpr const char Yards::label[];
 constexpr auto yards = QuantityMaker<Yards>{};
 
-struct Meters : decltype(Inches{} * mag<100>() / mag<254>() * mag<100>()) {};
+struct Meters : decltype(Inches{} * mag<100>() / mag<254>() * mag<100>()) {
+    static constexpr const char label[] = "m";
+};
+constexpr const char Meters::label[];
 static constexpr QuantityMaker<Meters> meters{};
 static_assert(are_units_quantity_equivalent(Centi<Meters>{} * mag<254>(), Inches{} * mag<100>()),
               "Double-check this ad hoc definition of meters");