Test basic functionality of Temporal.Instant.from

test/built-ins/Temporal/Instant/from/basic.js

@@ -0,0 +1,59 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.instant.from
+description: Basic functionality of Temporal.Instant.from
+features: [Temporal]
+---*/
+
+const baseValue = 217_178_580_000_000_000n;
+
+let instant = Temporal.Instant.from("1976-11-18T15:23Z");
+assert.sameValue(
+  instant.epochNanoseconds,
+  baseValue,
+  "ISO string with UTC designator and minutes precision"
+);
+
+instant = Temporal.Instant.from("1976-11-18T15:23:30Z");
+assert.sameValue(
+  instant.epochNanoseconds,
+  baseValue + 30_000_000_000n,
+  "ISO string with UTC designator and seconds precision"
+);
+
+instant = Temporal.Instant.from("1976-11-18T15:23:30.123Z");
+assert.sameValue(
+  instant.epochNanoseconds,
+  baseValue + 30_123_000_000n,
+  "ISO string with UTC designator and milliseconds precision"
+);
+
+instant = Temporal.Instant.from("1976-11-18T15:23:30.123456Z");
+assert.sameValue(
+  instant.epochNanoseconds,
+  baseValue + 30_123_456_000n,
+  "ISO string with UTC designator and microseconds precision"
+);
+
+instant = Temporal.Instant.from("1976-11-18T15:23:30.123456789Z");
+assert.sameValue(
+  instant.epochNanoseconds,
+  baseValue + 30_123_456_789n,
+  "ISO string with UTC designator and nanoseconds precision"
+);
+
+instant = Temporal.Instant.from("1976-11-18T15:23-01:00");
+assert.sameValue(
+  instant.epochNanoseconds,
+  baseValue + 3600_000_000_000n,
+  "ISO string with negative UTC offset"
+);
+
+instant = Temporal.Instant.from("1976-11-18T15:23+01:00");
+assert.sameValue(
+  instant.epochNanoseconds,
+  baseValue - 3600_000_000_000n,
+  "ISO string with positive UTC offset"
+);