Re-enable testSigningKey after fixing Native's fromIso8601 implementation

Author: lauzadis

runtime/auth/aws-signing-default/common/test/aws/smithy/kotlin/runtime/auth/awssigning/DefaultSignatureCalculatorTest.kt

@@ -33,7 +33,6 @@ class DefaultSignatureCalculatorTest {
     }
 
     // Test adapted from https://docs.aws.amazon.com/general/latest/gr/sigv4-calculate-signature.html
-    @IgnoreNative // FIXME Re-enable after Kotlin/Native Implementation. Need to fix parsing ISO 8601 to try all possible formats
     @Test
     fun testSigningKey() = runTest {
         val config = AwsSigningConfig {

runtime/runtime-core/common/test/aws/smithy/kotlin/runtime/time/InstantTest.kt

@@ -56,6 +56,10 @@ class InstantTest {
 
         // leap second - dropped to: 2020-12-31T23:59:59
         FromTest("2020-12-31T23:59:60Z", 1609459199, 0),
+
+        // condensed, date only
+        FromTest("20250205", 1738713600, 0),
+        FromTest("20231127", 1701043200, 0),
     )
 
     @Test

runtime/runtime-core/native/src/aws/smithy/kotlin/runtime/time/DateTimeFormats.kt

@@ -8,6 +8,7 @@ package aws.smithy.kotlin.runtime.time
 import kotlinx.datetime.LocalDate
 import kotlinx.datetime.UtcOffset
 import kotlinx.datetime.format.DateTimeComponents
+import kotlinx.datetime.format.DateTimeFormat
 import kotlinx.datetime.format.DayOfWeekNames
 import kotlinx.datetime.format.MonthNames
 import kotlinx.datetime.format.Padding
@@ -131,3 +132,14 @@ internal object DateTimeFormats {
         }
     }
 }
+
+/**
+ * ISO8601 condensed, date only. Corresponds to [TimestampFormat.ISO_8601_CONDENSED_DATE].
+ * Used only for _parsing_ ISO8601 condensed strings. Instant.parse() will fail if using [DateTimeFormats.ISO_8601_CONDENSED_DATE]
+ * because that is a [DateTimeFormat] which requires a time component to be present.
+ */
+internal val ISO_8601_CONDENSED_DATE_LOCALDATE = LocalDate.Format {
+        year()
+        monthNumber()
+        dayOfMonth()
+    }

runtime/runtime-core/native/src/aws/smithy/kotlin/runtime/time/InstantNative.kt

@@ -6,7 +6,13 @@
 package aws.smithy.kotlin.runtime.time
 
 import kotlinx.datetime.Clock
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atStartOfDayIn
 import kotlinx.datetime.format
+import kotlinx.datetime.toInstant
 import kotlin.time.Duration
 import kotlinx.datetime.Instant as KtInstant
 
@@ -62,17 +68,22 @@ public actual class Instant(internal val delegate: KtInstant) : Comparable<Insta
         /**
          * Parse an ISO-8601 formatted string into an [Instant]
          */
-        public actual fun fromIso8601(ts: String): Instant = try {
-            var parsed = DateTimeFormats.ISO_8601.parse(ts).apply {
-                // Handle leap seconds (23:59:60 becomes 23:59:59)
-                if (second == 60) {
-                    second = 59
+        public actual fun fromIso8601(ts: String): Instant {
+            val parseException = lazy { ParseException(ts, "Failed to parse $ts into an ISO-8601 timestamp", 0) }
+
+            listOf(
+                { DateTimeFormats.ISO_8601.parse(ts).apply { if (second == 60) second = 59 }.toInstantUsingOffset() },
+                { KtInstant.parse(ts, DateTimeFormats.ISO_8601_CONDENSED) },
+                { LocalDate.parse(ts, ISO_8601_CONDENSED_DATE_LOCALDATE).atStartOfDayIn(TimeZone.UTC) },
+            ).forEach { parseFn ->
+                try {
+                    return Instant(parseFn())
+                } catch (e: IllegalArgumentException) {
+                    parseException.value.addSuppressed(e)
                 }
             }
 
-            Instant(parsed.toInstantUsingOffset())
-        } catch (e: IllegalArgumentException) {
-            throw ParseException(ts, "Failed to parse $ts into an ISO-8601 timestamp", 0)
+            throw parseException.value
         }
 
         /**