Clean up uint16_t test a little more

au/quantity_test.cc

@@ -725,8 +725,10 @@ TEST(WillConversionTruncate, UsesModForIntegerTypes) {
 TEST(IsConversionLossy, CorrectlyDiscriminatesBetweenLossyAndLosslessConversions) {
     // We will check literally every representable value in the type, and make sure that the result
     // of `is_conversion_lossy()` matches perfectly with the inability to recover the initial value.
-    auto test_round_trip_for_every_uint8_value = [](auto source_units, auto target_units) {
-        for (int i = 0; i <= 65535; ++i) {
+    auto test_round_trip_for_every_uint16_value = [](auto source_units, auto target_units) {
+        for (int i = std::numeric_limits<uint16_t>::lowest();
+             i <= std::numeric_limits<uint16_t>::max();
+             ++i) {
             const auto original = source_units(static_cast<uint16_t>(i));
             const auto converted = original.coerce_as(target_units);
             const auto round_trip = converted.coerce_as(source_units);
@@ -753,10 +755,10 @@ TEST(IsConversionLossy, CorrectlyDiscriminatesBetweenLossyAndLosslessConversions
     };
 
     // Inches-to-feet tests truncation.
-    test_round_trip_for_every_uint8_value(inches, feet);
+    test_round_trip_for_every_uint16_value(inches, feet);
 
     // Feet-to-inches tests overflow.
-    test_round_trip_for_every_uint8_value(feet, inches);
+    test_round_trip_for_every_uint16_value(feet, inches);
 }
 
 TEST(AreQuantityTypesEquivalent, RequiresSameRepAndEquivalentUnits) {