Reproduce malformed feedback event handling in the UI

tools/chatgui-android/app/src/test/java/com/utun/chat/data/FeedbackEventTest.kt

@@ -0,0 +1,73 @@
+package com.utun.chat.data
+
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+import java.nio.charset.CharacterCodingException
+import org.junit.Assert.*
+import org.junit.Test
+
+/** Настоящий wire-разбор, используемый ViewModel; формат фиксируют chat_event.h и C-производители событий. */
+class FeedbackEventTest {
+    private fun changed(channel: String = "123", kind: Int = 1): ByteArray {
+        val text = channel.toByteArray(Charsets.UTF_8)
+        return byteArrayOf(text.size.toByte()) + text + ByteArray(32) { it.toByte() } + byteArrayOf(kind.toByte())
+    }
+    private fun result(id: Long = 7, flag: Int = 1, text: ByteArray = "{}".toByteArray()): ByteArray =
+        ByteBuffer.allocate(9 + text.size).order(ByteOrder.LITTLE_ENDIAN).putLong(id).put(flag.toByte()).put(text).array()
+
+    @Test fun changedEventKeepsCanonicalChannelMessageAndFeedbackKind() {
+        val event = requireNotNull(parseFeedbackChangedEvent(changed("9223372036854775807", 2)))
+        assertEquals("9223372036854775807", event.channelId); assertEquals(2, event.kind)
+        assertEquals("000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f", event.messageId)
+    }
+
+    @Test fun truncatedChangedEventsFailInsteadOfBeingSilentlyIgnored() {
+        assertThrows(IllegalArgumentException::class.java) { parseFeedbackChangedEvent(null) }
+        for (size in 0..34) assertThrows(IllegalArgumentException::class.java) { parseFeedbackChangedEvent(ByteArray(size)) }
+        val valid = changed()
+        assertThrows(IllegalArgumentException::class.java) { parseFeedbackChangedEvent(valid.copyOf(valid.size - 1)) }
+        assertThrows(IllegalArgumentException::class.java) { parseFeedbackChangedEvent(valid + byteArrayOf(0)) }
+    }
+
+    @Test fun invalidChannelAndUnknownKindCannotTriggerASnapshotRequest() {
+        for (channel in listOf("", "0", "01", "-1", "+1", "1a", "é", "9223372036854775808", "1".repeat(20))) {
+            assertThrows(IllegalArgumentException::class.java) { parseFeedbackChangedEvent(changed(channel)) }
+        }
+        for (kind in listOf(0, 3, 255)) {
+            assertThrows(IllegalArgumentException::class.java) { parseFeedbackChangedEvent(changed(kind = kind)) }
+        }
+    }
+
+    @Test fun resultPreservesAllRequestBitsAndUnicodeErrorText() {
+        val id = 0xfedcba9876543210uL.toLong()
+        val event = requireNotNull(parseFeedbackResultEvent(result(id, 0, "{\"error\":\"Отказ 😀\"}".toByteArray())))
+        assertEquals(id, event.requestId); assertFalse(event.success); assertEquals("Отказ 😀", event.json.getString("error"))
+        val background = requireNotNull(parseFeedbackResultEvent(result(0)))
+        assertEquals(0L, background.requestId); assertTrue(background.success)
+    }
+
+    @Test fun truncatedResultAndEmptyJsonFailForTheCallerToReport() {
+        assertThrows(IllegalArgumentException::class.java) { parseFeedbackResultEvent(null) }
+        for (size in 0..9) assertThrows(IllegalArgumentException::class.java) { parseFeedbackResultEvent(ByteArray(size)) }
+    }
+
+    @Test fun successFlagMustBeExactlyZeroOrOne() {
+        for (flag in listOf(2, 127, 255)) {
+            assertThrows(IllegalArgumentException::class.java) { parseFeedbackResultEvent(result(flag = flag)) }
+        }
+    }
+
+    @Test fun invalidUtf8AndMalformedJsonAreNotReplacedByAValidSnapshot() {
+        val corrupt = "{\"text\":\"".toByteArray() + byteArrayOf(0xff.toByte()) + "\"}".toByteArray()
+        assertThrows(CharacterCodingException::class.java) { parseFeedbackResultEvent(result(text = corrupt)) }
+        assertThrows(Exception::class.java) { parseFeedbackResultEvent(result(text = "{broken}".toByteArray())) }
+    }
+
+    @Test fun committedAckAndCatalogRemainDifferentFromASnapshot() {
+        val ack = "{\"ch\":\"123\",\"message_id\":\"${"ab".repeat(32)}\",\"committed\":true,\"snapshot_pending\":true}"
+        val event = requireNotNull(parseFeedbackResultEvent(result(text = ack.toByteArray())))
+        assertTrue(event.success); assertTrue(event.json.getBoolean("committed")); assertTrue(event.json.getBoolean("snapshot_pending"))
+        val catalog = requireNotNull(parseFeedbackResultEvent(result(text = "{\"catalog\":[]}".toByteArray())))
+        assertTrue(catalog.json.has("catalog")); assertFalse(catalog.json.has("message_id"))
+    }
+}