[Link new device] Fix and add tests.

Author: bmarty

features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodeStateProvider.kt

@@ -25,7 +25,7 @@ class ShowQrCodeStateProvider : PreviewParameterProvider<ShowQrCodeState> {
         )
 }
 
-private fun aShowQrCodeState(
+internal fun aShowQrCodeState(
     data1: AsyncData<String> = AsyncData.Success("DATA"),
     data2: AsyncData<String> = AsyncData.Uninitialized,
     dataToRender: Int = 1,

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodePresenterTest.kt

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalCoroutinesApi::class)
+
+package io.element.android.features.linknewdevice.impl.screens.qrcode
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.linknewdevice.impl.LinkNewMobileHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileHandler
+import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
+import io.element.android.libraries.matrix.test.FakeMatrixClient
+import io.element.android.libraries.matrix.test.linknewdevice.FakeLinkMobileHandler
+import io.element.android.tests.testutils.WarmUpRule
+import io.element.android.tests.testutils.lambda.lambdaRecorder
+import io.element.android.tests.testutils.test
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.runCurrent
+import kotlinx.coroutines.test.runTest
+import org.junit.Rule
+import org.junit.Test
+
+class ShowQrCodePresenterTest {
+    @get:Rule
+    val warmUpRule = WarmUpRule()
+
+    @Test
+    fun `present - initial state`() = runTest {
+        createPresenter().test {
+            val initialState = awaitItem()
+            assertThat(initialState.data1.dataOrNull()).isEqualTo("DATA")
+            assertThat(initialState.data2.isUninitialized()).isTrue()
+            assertThat(initialState.dataToRender).isEqualTo(1)
+        }
+    }
+
+    @Test
+    fun `present - when handler emits QrRotating, the presenter requests to rotate the QrCode`() = runTest {
+        val linkMobileHandler = FakeLinkMobileHandler(
+            startResult = {},
+        )
+        val createLinkMobileHandlerResult = lambdaRecorder<Result<LinkMobileHandler>> {
+            Result.success(linkMobileHandler)
+        }
+        val matrixClient = FakeMatrixClient(
+            sessionCoroutineScope = backgroundScope,
+            createLinkMobileHandlerResult = createLinkMobileHandlerResult,
+        )
+        val linkNewMobileHandler = LinkNewMobileHandler(matrixClient)
+        linkNewMobileHandler.createAndStartNewHandler()
+        createPresenter(
+            linkNewMobileHandler = linkNewMobileHandler,
+        ).test {
+            awaitItem()
+            linkMobileHandler.emitStep(
+                LinkMobileStep.QrRotating
+            )
+            runCurrent()
+            val finalState = awaitItem()
+            assertThat(finalState.data2.isLoading()).isTrue()
+            assertThat(finalState.dataToRender).isEqualTo(2)
+            createLinkMobileHandlerResult.assertions().isCalledExactly(2)
+        }
+    }
+
+    @Test
+    fun `present - when handler emits QrRotating, the presenter requests to rotate the QrCode and the code is rotated`() = runTest {
+        val linkMobileHandler = FakeLinkMobileHandler(
+            startResult = {},
+        )
+        val matrixClient = FakeMatrixClient(
+            sessionCoroutineScope = backgroundScope,
+            createLinkMobileHandlerResult = { Result.success(linkMobileHandler) },
+        )
+        val linkNewMobileHandler = LinkNewMobileHandler(matrixClient)
+        linkNewMobileHandler.createAndStartNewHandler()
+        createPresenter(
+            linkNewMobileHandler = linkNewMobileHandler,
+        ).test {
+            awaitItem()
+            linkMobileHandler.emitStep(
+                LinkMobileStep.QrRotating
+            )
+            runCurrent()
+            linkMobileHandler.emitStep(
+                LinkMobileStep.QrReady("DATA2")
+            )
+            val finalState = awaitItem()
+            assertThat(finalState.data1.dataOrNull()).isEqualTo("DATA")
+            assertThat(finalState.data2.dataOrNull()).isEqualTo("DATA2")
+            assertThat(finalState.dataToRender).isEqualTo(2)
+        }
+    }
+
+    private fun createPresenter(
+        linkNewMobileHandler: LinkNewMobileHandler = LinkNewMobileHandler(FakeMatrixClient()),
+    ) = ShowQrCodePresenter(
+        initialData = "DATA",
+        linkNewMobileHandler = linkNewMobileHandler,
+    )
+}

features/linknewdevice/impl/src/test/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodeViewTest.kt

@@ -37,7 +37,7 @@ class ShowQrCodeViewTest {
     ) {
         setContent {
             ShowQrCodeView(
-                data = "DATA",
+                state = aShowQrCodeState(),
                 onBackClick = onBackClick,
             )
         }