feat(chat): stabilize multi-image attachment picker (#986)

app/src/test/java/com/m57/hermescontrol/ExternalActivityLifecycleGuardTest.kt

@@ -0,0 +1,101 @@
+package com.m57.hermescontrol
+
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+
+class ExternalActivityLifecycleGuardTest {
+    @Before
+    fun setUp() {
+        ExternalActivityLifecycleGuard.resetForTest()
+    }
+
+    @After
+    fun tearDown() {
+        ExternalActivityLifecycleGuard.resetForTest()
+    }
+
+    @Test
+    fun externalActivityLaunch_acquiresConnectionLeaseBeforePreparingServiceAndLaunching() {
+        val calls = mutableListOf<String>()
+
+        ExternalActivityLifecycleGuard.launchExternalActivity(
+            acquireConnectionLease = { calls += "acquire" },
+            releaseConnectionLease = { calls += "release" },
+            prepareForBackground = { calls += "prepare" },
+            cleanupAfterLaunchFailure = { calls += "cleanup" },
+            scheduleTimeout = { _, _ -> },
+            launch = { calls += "launch" },
+        )
+
+        assertEquals(listOf("acquire", "prepare", "launch"), calls)
+    }
+
+    @Test
+    fun transientResumeDuringPicker_doesNotReleaseLeaseUntilResultReturns() {
+        var released = false
+
+        ExternalActivityLifecycleGuard.launchExternalActivity(
+            acquireConnectionLease = {},
+            releaseConnectionLease = { released = true },
+            prepareForBackground = {},
+            cleanupAfterLaunchFailure = {},
+            scheduleTimeout = { _, _ -> },
+            launch = {},
+        )
+        ExternalActivityLifecycleGuard.onHostPaused()
+        ExternalActivityLifecycleGuard.onHostResumed()
+
+        assertFalse(released)
+
+        ExternalActivityLifecycleGuard.onHostPaused()
+        ExternalActivityLifecycleGuard.externalActivityReturned()
+
+        assertFalse(released)
+
+        ExternalActivityLifecycleGuard.onHostResumed()
+
+        assertTrue(released)
+    }
+
+    @Test
+    fun abandonedPicker_timeoutReleasesConnectionLease() {
+        var timeoutAction: (() -> Unit)? = null
+        var released = false
+
+        ExternalActivityLifecycleGuard.launchExternalActivity(
+            acquireConnectionLease = {},
+            releaseConnectionLease = { released = true },
+            prepareForBackground = {},
+            cleanupAfterLaunchFailure = {},
+            scheduleTimeout = { _, action -> timeoutAction = action },
+            launch = {},
+        )
+        ExternalActivityLifecycleGuard.onHostPaused()
+
+        timeoutAction?.invoke()
+
+        assertTrue(released)
+    }
+
+    @Test
+    fun failedExternalActivityLaunch_cleansUpServiceAndConnectionLease() {
+        val calls = mutableListOf<String>()
+
+        runCatching {
+            ExternalActivityLifecycleGuard.launchExternalActivity(
+                acquireConnectionLease = { calls += "acquire" },
+                releaseConnectionLease = { calls += "release" },
+                prepareForBackground = { calls += "prepare" },
+                cleanupAfterLaunchFailure = { calls += "cleanup" },
+                scheduleTimeout = { _, _ -> },
+                launch = { error("picker unavailable") },
+            )
+        }
+
+        assertEquals(listOf("acquire", "prepare", "cleanup", "release"), calls)
+    }
+}