Coverage: Date arithmetic is floating point

test/built-ins/Date/UTC/fp-evaluation-order.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2020 Kevin Gibbons. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-date.utc
+description: arithmetic in Date is done on floating-point numbers
+info: |
+  [...]
+  Return TimeClip(MakeDate(MakeDay(yr, m, dt), MakeTime(h, min, s, milli))).
+
+  #sec-maketime
+
+  Let _t_ be ((_h_ `*` msPerHour `+` _m_ `*` msPerMinute) `+` _s_ `*` msPerSecond) `+` _milli_, performing the arithmetic according to IEEE 754-2019 rules (that is, as if using the ECMAScript operators `*` and `+`).
+
+  #sec-makedate
+
+  Return day × msPerDay + time.
+---*/
+
+assert.sameValue(Date.UTC(1970, 0, 1, 80063993375, 29, 1, -288230376151711740), 29312, 'order of operations / precision in MakeTime');
+assert.sameValue(Date.UTC(1970, 0, 213503982336, 0, 0, 0, -18446744073709552000), 34447360, 'precision in MakeDate');