Post several pictures as one story sequence

Android half of ios#53, spec §6.23. Each item is an ordinary story envelope carrying a `set` naming the sequence, its position and its size. 🔴 One envelope per item rather than an array of attachments. The array fails the single-`att` guard on any build predating §6.23 and renders the whole set as a message in the conversation; separate envelopes degrade to several stories in order, which every existing build already draws. 🔴 `setExpiry` takes the earliest stamp. Items are required to carry the same one, but a sender can write different ones, and if the latest won the difference would keep part of a sequence alive after the rest had gone. A zero is skipped rather than read as "expires at the epoch", which would kill the whole set. ⚠️ `groupedStories` renders what arrived: `n` is a claim, any item can fail to arrive, and a missing one is indistinguishable from one never sent. Stories with no set are keyed so two of them cannot collide. ⚠️ The set is persisted, or a relaunch scatters every sequence back into loose stories. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-09-02 17:48:16 -04:00
parent 861b14fcde
commit d525ef3d69
4 changed files with 231 additions and 1 deletions
@@ -0,0 +1,129 @@
+package io.flamenet.e2e
+
+import org.json.JSONObject
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+/** Multi-item stories (spec §6.23, ios#53). */
+class StorySetTest {
+
+    private fun ref(id: Int, expires: Double = 100.0) = Attachment.Ref(
+        kind = Attachment.STORY, id = "b$id", key = ByteArray(32),
+        digest = ByteArray(32), bytes = 1, mime = "image/jpeg",
+        width = 1, height = 1, duration = 0.0, expires = expires,
+    )
+
+    private fun item(id: Int, set: String?, i: Int = 0, n: Int = 1, expires: Double = 100.0) =
+        Vault.Story(
+            id = "s$id", authorId = 7, mine = false, ref = ref(id, expires),
+            caption = "", postedAt = id.toLong(),
+            set = set?.let { Content.StorySet(it, i, n) },
+        )
+
+    // -- The wire -------------------------------------------------------------
+
+    @Test
+    fun `an item carries its set position and size`() {
+        val wire = Content.attachment(ref(1), storySet = Content.StorySet("set-1", 2, 5))
+        val content = Content.parse(wire)
+        assertEquals("set-1", content.storySet?.id)
+        assertEquals(2, content.storySet?.i)
+        assertEquals(5, content.storySet?.n)
+    }
+
+    /**
+     * 🔴 One envelope per item. An array of attachments would fail the
+     * single-`att` guard on any build predating §6.23 and render the whole set
+     * as a message in the conversation.
+     */
+    @Test
+    fun `an item is an ordinary story envelope`() {
+        val json = JSONObject(Content.attachment(ref(1), storySet = Content.StorySet("s", 0, 2)))
+        assertEquals(Attachment.STORY, json.getString("kind"))
+        assertTrue(json.has("att"))
+        assertFalse(json.has("atts"))
+    }
+
+    @Test
+    fun `an ordinary story has no set`() {
+        assertNull(Content.parse(Content.attachment(ref(1))).storySet)
+    }
+
+    // -- Grouping -------------------------------------------------------------
+
+    @Test
+    fun `items of one set are grouped in position order`() {
+        val groups = Vault.groupedStories(listOf(
+            item(3, "a", i = 2, n = 3), item(1, "a", i = 0, n = 3), item(2, "a", i = 1, n = 3)))
+        assertEquals(1, groups.size)
+        assertEquals(listOf("s1", "s2", "s3"), groups[0].map { it.id })
+    }
+
+    /** ⚠️ `n` says three; two came. Render what arrived. */
+    @Test
+    fun `a partly arrived set is still rendered`() {
+        val groups = Vault.groupedStories(listOf(
+            item(1, "a", i = 0, n = 3), item(3, "a", i = 2, n = 3)))
+        assertEquals(1, groups.size)
+        assertEquals(2, groups[0].size)
+    }
+
+    /** ⚠️ Two singles must not collide just because neither has a set id. */
+    @Test
+    fun `two sets and a single stay apart`() {
+        val groups = Vault.groupedStories(listOf(
+            item(1, "a", i = 0, n = 2), item(2, "b"), item(3, null), item(4, "a", i = 1, n = 2)))
+        assertEquals(3, groups.size)
+        assertEquals(listOf("s1", "s4"), groups[0].map { it.id })
+    }
+
+    // -- Expiry ---------------------------------------------------------------
+
+    /** 🔴 The earliest wins, so a sender cannot outlive part of its own set. */
+    @Test
+    fun `a set expires at its earliest stamp`() {
+        assertEquals(100.0, Vault.setExpiry(listOf(
+            item(1, "a", expires = 300.0),
+            item(2, "a", expires = 100.0),
+            item(3, "a", expires = 200.0))))
+    }
+
+    /** ⚠️ A zero means "never" and must not be read as "expires at the epoch". */
+    @Test
+    fun `a zero stamp does not expire the whole set`() {
+        assertEquals(500.0, Vault.setExpiry(listOf(
+            item(1, "a", expires = 0.0), item(2, "a", expires = 500.0))))
+    }
+
+    @Test
+    fun `a set of never-expiring items never expires`() {
+        assertEquals(0.0, Vault.setExpiry(listOf(
+            item(1, "a", expires = 0.0), item(2, "a", expires = 0.0))))
+    }
+
+    // -- Storage --------------------------------------------------------------
+
+    private class MapStorage : Vault.Storage {
+        val records = LinkedHashMap<String, ByteArray>()
+        override fun read(name: String) = records[name]
+        override fun write(name: String, bytes: ByteArray) { records[name] = bytes }
+        override fun delete(name: String) { records.remove(name) }
+        override fun names() = records.keys.toList()
+    }
+
+    /** ⚠️ The set survives a reload, or a relaunch scatters every sequence. */
+    @Test
+    fun `the set survives the vault round trip`() {
+        val vault = Vault(MapStorage(),
+            javax.crypto.KeyGenerator.getInstance("AES").apply { init(256) }.generateKey())
+        val now = System.currentTimeMillis() / 1000.0
+        vault.saveStories(listOf(item(1, "a", i = 1, n = 4, expires = now + 600)), now)
+        val back = vault.loadStories().single()
+        assertEquals("a", back.set?.id)
+        assertEquals(1, back.set?.i)
+        assertEquals(4, back.set?.n)
+    }
+}