Using FileStateStore instead of MemoryStore in TestApp

test-app/android-views/src/main/kotlin/com/example/redwood/testing/android/views/FileStateStore.kt

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2023 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.example.redwood.testing.android.views
+
+import app.cash.redwood.treehouse.StateSnapshot
+import app.cash.redwood.treehouse.StateStore
+import kotlinx.serialization.decodeFromString
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import okio.FileNotFoundException
+import okio.FileSystem
+import okio.Path
+
+/**
+ * Limited state store that creates a new file for each snapshot.
+ *
+ * This doesn't implement eviction.
+ */
+class FileStateStore(
+  private val json: Json,
+  private val fileSystem: FileSystem,
+  private val directory: Path,
+) : StateStore {
+  init {
+    fileSystem.createDirectories(directory)
+    // TODO add a mechanism to delete files older than 24 hours
+  }
+
+  override suspend fun put(id: String, value: StateSnapshot) {
+    val path = directory / "$id.state"
+    val tmpPath = directory / "$id.state.tmp"
+    fileSystem.write(tmpPath) {
+      writeUtf8(json.encodeToString(value))
+    }
+    fileSystem.atomicMove(tmpPath, path)
+  }
+
+  override suspend fun get(id: String): StateSnapshot? {
+    return try {
+      val path = directory / "$id.state"
+      fileSystem.read(path) {
+        json.decodeFromString<StateSnapshot>(readUtf8())
+      }
+    } catch (e: FileNotFoundException) {
+      null
+    }
+  }
+}

test-app/android-views/src/main/kotlin/com/example/redwood/testing/android/views/TestAppActivity.kt

@@ -40,6 +40,8 @@ import kotlinx.coroutines.cancel
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.serialization.json.Json
 import okhttp3.OkHttpClient
+import okio.FileSystem
+import okio.Path.Companion.toOkioPath
 
 class TestAppActivity : ComponentActivity() {
   private val scope: CoroutineScope = CoroutineScope(Main)
@@ -81,6 +83,11 @@ class TestAppActivity : ComponentActivity() {
       context = applicationContext,
       httpClient = httpClient,
       manifestVerifier = ManifestVerifier.NO_SIGNATURE_CHECKS,
+      stateStore = FileStateStore(
+        json = Json,
+        fileSystem = FileSystem.SYSTEM,
+        directory = applicationContext.getDir("TreehouseState", MODE_PRIVATE).toOkioPath(),
+      ),
     )
 
     val manifestUrlFlow = flowOf("http://10.0.2.2:8080/manifest.zipline.json")