diff --git a/test/built-ins/Temporal/Instant/from/argument-string.js b/test/built-ins/Temporal/Instant/from/argument-string.js
index bfea63e3aa..923158e21c 100644
--- a/test/built-ins/Temporal/Instant/from/argument-string.js
+++ b/test/built-ins/Temporal/Instant/from/argument-string.js
@@ -35,6 +35,33 @@ const tests = [
   ['+0019761118T152330.1+00:00', 217178610100000000n],
   ['+0019761118T152330.1+0000', 217178610100000000n],
   ['1976-11-18T15:23:30+00', 217178610000000000n],
+  ['1976-11-18T15:23:30.123456789-00:00:00', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.0', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.00', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.0000', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.00000', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000000', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.0000000', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.00000000', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000000000', 217178610123456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.1', 217178610223456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.01', 217178610133456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.001', 217178610124456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.0001', 217178610123556789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.00001', 217178610123466789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000001', 217178610123457789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.0000001', 217178610123456889n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.00000001', 217178610123456799n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000000001', 217178610123456790n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.100000000', 217178610223456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.010000000', 217178610133456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.001000000', 217178610124456789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000100000', 217178610123556789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000010000', 217178610123466789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000001000', 217178610123457789n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000000100', 217178610123456889n],
+  ['1976-11-18T15:23:30.123456789-00:00:00.000000010', 217178610123456799n],
   ['1976-11-18T15Z', 217177200000000000n],
   ['1976-11-18T15:23:30.123456789Z[u-ca=discord]', 217178610123456789n],
   ['1976-11-18T15:23:30.123456789Z[+00]', 217178610123456789n],