2 files changed, 76 insertions, 2 deletions
diff --git a/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Time.kt b/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Time.kt
index 962e004..37b6606 100644
--- a/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Time.kt
+++ b/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Time.kt
@@ -18,6 +18,12 @@ package net.taler.common
 
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonPrimitive
+import kotlinx.serialization.json.JsonTransformingSerializer
+import kotlinx.serialization.json.contentOrNull
+import kotlinx.serialization.json.longOrNull
 import net.taler.common.Duration.Companion.FOREVER
 import kotlin.math.max
 
@@ -26,11 +32,12 @@ expect fun nowMillis(): Long
 @Serializable
 data class Timestamp(
     @SerialName("t_ms")
+    @Serializable(NeverSerializer::class)
     val ms: Long
 ) : Comparable<Timestamp> {
 
     companion object {
-        const val NEVER: Long = -1  // TODO or UINT64_MAX?
+        const val NEVER: Long = -1
         fun now(): Timestamp = Timestamp(nowMillis())
     }
 
@@ -73,9 +80,27 @@ data class Duration(
      * Duration in milliseconds.
      */
     @SerialName("d_ms")
+    @Serializable(ForeverSerializer::class)
     val ms: Long
 ) {
     companion object {
-        const val FOREVER: Long = -1  // TODO or UINT64_MAX?
+        const val FOREVER: Long = -1
     }
 }
+
+abstract class MinusOneSerializer(private val keyword: String) :
+    JsonTransformingSerializer<Long>(Long.serializer(), keyword) {
+
+    override fun readTransform(element: JsonElement): JsonElement {
+        return if (element.contentOrNull == keyword) return JsonPrimitive(-1)
+        else super.readTransform(element)
+    }
+
+    override fun writeTransform(element: JsonElement): JsonElement {
+        return if (element.longOrNull == -1L) return JsonPrimitive(keyword)
+        else element
+    }
+}
+
+object NeverSerializer : MinusOneSerializer("never")
+object ForeverSerializer : MinusOneSerializer("forever")
diff --git a/taler-kotlin-common/src/commonTest/kotlin/net/taler/common/TimeTest.kt b/taler-kotlin-common/src/commonTest/kotlin/net/taler/common/TimeTest.kt
new file mode 100644
index 0000000..3ee0a99
--- /dev/null
+++ b/taler-kotlin-common/src/commonTest/kotlin/net/taler/common/TimeTest.kt
@@ -0,0 +1,49 @@
+/*
+ * This file is part of GNU Taler
+ * (C) 2020 Taler Systems S.A.
+ *
+ * GNU Taler is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3, or (at your option) any later version.
+ *
+ * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+package net.taler.common
+
+import kotlinx.serialization.UnstableDefault
+import kotlinx.serialization.json.Json.Default.parse
+import kotlinx.serialization.json.Json.Default.stringify
+import net.taler.common.Timestamp.Companion.NEVER
+import kotlin.random.Random
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+// TODO test other functionality of Timestamp and Duration
+@UnstableDefault
+class TimeTest {
+
+    @Test
+    fun testSerialize() {
+        for (i in 0 until 42) {
+            val t = Random.nextLong()
+            assertEquals("""{"t_ms":$t}""", stringify(Timestamp.serializer(), Timestamp(t)))
+        }
+        assertEquals("""{"t_ms":"never"}""", stringify(Timestamp.serializer(), Timestamp(NEVER)))
+    }
+
+    @Test
+    fun testDeserialize() {
+        for (i in 0 until 42) {
+            val t = Random.nextLong()
+            assertEquals(Timestamp(t), parse(Timestamp.serializer(), """{ "t_ms": $t }"""))
+        }
+        assertEquals(Timestamp(NEVER), parse(Timestamp.serializer(), """{ "t_ms": "never" }"""))
+    }
+
+}