[#270] Add regression tests for assets

sdk-lib/src/androidTest/java/cash/z/ecc/android/sdk/AssetTest.kt

@@ -0,0 +1,108 @@
+package cash.z.ecc.android.sdk
+
+import android.content.Context
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.filters.SmallTest
+import cash.z.ecc.android.sdk.tool.WalletBirthdayTool
+import cash.z.ecc.android.sdk.type.ZcashNetwork
+import org.json.JSONObject
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class AssetTest {
+    @Test
+    @SmallTest
+    fun birthday_height_from_filename() {
+        assertEquals(123, WalletBirthdayTool.birthdayHeight("123.json"))
+    }
+
+    @Test
+    @SmallTest
+    fun validate_mainnet_assets() {
+        val network = ZcashNetwork.Mainnet
+        val assets = listAssets(network)
+
+        assertFilesExist(assets)
+        assertFilenames(assets)
+        assertFileContents(network, assets)
+    }
+
+    @Test
+    @SmallTest
+    fun validate_testnet_assets() {
+        val network = ZcashNetwork.Testnet
+        val assets = listAssets(network)
+
+        assertFilesExist(assets)
+        assertFilenames(assets)
+        assertFileContents(network, assets)
+    }
+
+    private fun assertFilesExist(files: Array<String>?) {
+        assertFalse(files.isNullOrEmpty())
+    }
+
+    private fun assertFilenames(files: Array<String>?) {
+        files?.forEach {
+            val split = it.split('.')
+            assertEquals(2, split.size)
+
+            val intString = split.first()
+            val extensionString = split.last()
+
+            // Will throw exception if cannot be parsed
+            intString.toInt()
+
+            assertEquals("json", extensionString)
+        }
+    }
+
+    private fun assertFileContents(network: ZcashNetwork, files: Array<String>?) {
+        files?.map { filename ->
+            val filePath = "${WalletBirthdayTool.birthdayDirectory(network)}/$filename"
+            ApplicationProvider.getApplicationContext<Context>().assets.open(filePath)
+                .use { inputSteam ->
+                    inputSteam.bufferedReader().use { bufferedReader ->
+                        val slurped = bufferedReader.readText()
+
+                        JsonFile(JSONObject(slurped), filename)
+                    }
+                }
+        }?.forEach {
+            val jsonObject = it.jsonObject
+            assertTrue(jsonObject.has("network"))
+            assertTrue(jsonObject.has("height"))
+            assertTrue(jsonObject.has("hash"))
+            assertTrue(jsonObject.has("time"))
+            assertTrue(jsonObject.has("tree"))
+
+            val expectedNetworkName = when (network) {
+                ZcashNetwork.Mainnet -> "main"
+                ZcashNetwork.Testnet -> "test"
+            }
+            assertEquals("File: ${it.filename}", expectedNetworkName, jsonObject.getString("network"))
+
+            assertEquals(
+                "File: ${it.filename}",
+                WalletBirthdayTool.birthdayHeight(it.filename),
+                jsonObject.getInt("height")
+            )
+
+            // In the future, additional validation of the JSON can be added
+        }
+    }
+
+    private data class JsonFile(val jsonObject: JSONObject, val filename: String)
+
+    companion object {
+        fun listAssets(network: ZcashNetwork) = WalletBirthdayTool.listBirthdayDirectoryContents(
+            ApplicationProvider.getApplicationContext<Context>(),
+            WalletBirthdayTool.birthdayDirectory(network)
+        )
+    }
+}

sdk-lib/src/main/java/cash/z/ecc/android/sdk/tool/WalletBirthdayTool.kt

@@ -1,15 +1,16 @@
 package cash.z.ecc.android.sdk.tool
 
 import android.content.Context
+import androidx.annotation.VisibleForTesting
 import cash.z.ecc.android.sdk.exception.BirthdayException
 import cash.z.ecc.android.sdk.ext.twig
 import cash.z.ecc.android.sdk.type.WalletBirthday
 import cash.z.ecc.android.sdk.type.ZcashNetwork
 import com.google.gson.Gson
 import com.google.gson.stream.JsonReader
+import java.io.IOException
 import java.io.InputStreamReader
 import java.util.Arrays
-import java.util.Locale
 
 /**
  * Tool for loading checkpoints for the wallet, based on the height at which the wallet was born.
@@ -17,7 +18,7 @@ import java.util.Locale
  * @param appContext needed for loading checkpoints from the app's assets directory.
  */
 class WalletBirthdayTool(appContext: Context) {
-    val context = appContext.applicationContext
+    private val context = appContext.applicationContext
 
     /**
      * Load the nearest checkpoint to the given birthday height. If null is given, then this
@@ -51,13 +52,23 @@ class WalletBirthdayTool(appContext: Context) {
                     )
             }
 
+        // TODO: This method performs disk IO; convert to suspending function
+        // Converting this to suspending will then propagate
+        @Throws(IOException::class)
+        internal fun listBirthdayDirectoryContents(context: Context, directory: String) =
+            context.assets.list(directory)
+
         /**
          * Returns the directory within the assets folder where birthday data
          * (i.e. sapling trees for a given height) can be found.
          */
-        private fun birthdayDirectory(network: ZcashNetwork): String {
+        @VisibleForTesting
-            return "saplingtree/${network.networkName.toLowerCase(Locale.US)}"
+        internal fun birthdayDirectory(network: ZcashNetwork) =
-        }
+            "saplingtree/${network.networkName.lowercase()}"
+
+        internal fun birthdayHeight(fileName: String) = fileName.split('.').first().toInt()
+
+        private fun Array<String>.sortDescending() = apply { sortByDescending { birthdayHeight(it) } }
 
         /**
          * Load the given birthday file from the assets of the given context. When no height is
@@ -76,16 +87,7 @@ class WalletBirthdayTool(appContext: Context) {
         ): WalletBirthday {
             twig("loading birthday from assets: $birthdayHeight")
             val directory = birthdayDirectory(network)
-            val treeFiles =
+            val treeFiles = listBirthdayDirectoryContents(context, directory)?.sortDescending()
-                context.assets.list(directory)?.apply {
-                    sortByDescending { fileName ->
-                        try {
-                            fileName.split('.').first().toInt()
-                        } catch (t: Throwable) {
-                            network.saplingActivationHeight
-                        }
-                    }
-                }
             if (treeFiles.isNullOrEmpty()) throw BirthdayException.MissingBirthdayFilesException(
                 directory
             )
@@ -94,7 +96,7 @@ class WalletBirthdayTool(appContext: Context) {
             try {
                 file = if (birthdayHeight == null) treeFiles.first() else {
                     treeFiles.first {
-                        it.split(".").first().toInt() <= birthdayHeight
+                        birthdayHeight(it) <= birthdayHeight
                     }
                 }
             } catch (t: Throwable) {