Write unit test for computing user agent user case.

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/network/ComputeUserAgentUseCase.kt

@@ -40,14 +40,10 @@ class ComputeUserAgentUseCase @Inject constructor() {
                     it.matches("\\A\\p{ASCII}*\\z".toRegex())
                 }
                 ?: run {
-                    // Use appPackageName instead of appName if appName contains any non-ASCII character
+                    // Use appPackageName instead of appName if appName is null or contains any non-ASCII character
                     appPackageName
                 }
-        val appVersion = tryOrNull { pm.getPackageInfo(context.applicationContext.packageName, 0).versionName }
+        val appVersion = tryOrNull { pm.getPackageInfo(context.applicationContext.packageName, 0).versionName } ?: FALLBACK_APP_VERSION
-
-        if (appName.isNullOrEmpty() || appVersion.isNullOrEmpty()) {
-            return tryOrNull { System.getProperty("http.agent") } ?: ("Java" + System.getProperty("java.version"))
-        }
 
         val deviceManufacturer = Build.MANUFACTURER
         val deviceModel = Build.MODEL
@@ -77,4 +73,8 @@ class ComputeUserAgentUseCase @Inject constructor() {
             append(")")
         }
     }
+
+    companion object {
+        const val FALLBACK_APP_VERSION = "0.0.0"
+    }
 }

matrix-sdk-android/src/test/java/org/matrix/android/sdk/internal/network/ComputeUserAgentUseCaseTest.kt

@@ -0,0 +1,149 @@
+/*
+ * Copyright 2022 The Matrix.org Foundation C.I.C.
+ *
+ * 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 org.matrix.android.sdk.internal.network
+
+import android.content.Context
+import android.content.pm.ApplicationInfo
+import android.content.pm.PackageInfo
+import android.content.pm.PackageManager
+import android.os.Build
+import io.mockk.every
+import io.mockk.mockk
+import org.amshove.kluent.shouldBeEqualTo
+import org.junit.Before
+import org.junit.Test
+import org.matrix.android.sdk.BuildConfig
+import java.lang.Exception
+
+private const val A_PACKAGE_NAME = "org.matrix.sdk"
+private const val AN_APP_NAME = "Element"
+private const val A_NON_ASCII_APP_NAME = "Élement"
+private const val AN_APP_VERSION = "1.5.1"
+private const val A_FLAVOUR = "GooglePlay"
+
+class ComputeUserAgentUseCaseTest {
+
+    private val context = mockk<Context>()
+    private val packageManager = mockk<PackageManager>()
+    private val applicationInfo = mockk<ApplicationInfo>()
+    private val packageInfo = mockk<PackageInfo>()
+
+    private val computeUserAgentUseCase = ComputeUserAgentUseCase()
+
+    @Before
+    fun setUp() {
+        every { context.applicationContext } returns context
+        every { context.packageName } returns A_PACKAGE_NAME
+        every { context.packageManager } returns packageManager
+        every { packageManager.getApplicationInfo(any(), any()) } returns applicationInfo
+        every { packageManager.getPackageInfo(any<String>(), any()) } returns packageInfo
+    }
+
+    @Test
+    fun `given a non-null app name and app version when computing user agent then returns expected user agent`() {
+        // Given
+        givenAppName(AN_APP_NAME)
+        givenAppVersion(AN_APP_VERSION)
+
+        // When
+        val result = computeUserAgentUseCase.execute(context, A_FLAVOUR)
+
+        // Then
+        val expectedUserAgent = constructExpectedUserAgent(AN_APP_NAME, AN_APP_VERSION)
+        result shouldBeEqualTo expectedUserAgent
+    }
+
+    @Test
+    fun `given a null app name when computing user agent then returns user agent with package name instead of app name`() {
+        // Given
+        givenAppName(null)
+        givenAppVersion(AN_APP_VERSION)
+
+        // When
+        val result = computeUserAgentUseCase.execute(context, A_FLAVOUR)
+
+        // Then
+        val expectedUserAgent = constructExpectedUserAgent(A_PACKAGE_NAME, AN_APP_VERSION)
+        result shouldBeEqualTo expectedUserAgent
+    }
+
+    @Test
+    fun `given a non-ascii app name when computing user agent then returns user agent with package name instead of app name`() {
+        // Given
+        givenAppName(A_NON_ASCII_APP_NAME)
+        givenAppVersion(AN_APP_VERSION)
+
+        // When
+        val result = computeUserAgentUseCase.execute(context, A_FLAVOUR)
+
+        // Then
+        val expectedUserAgent = constructExpectedUserAgent(A_PACKAGE_NAME, AN_APP_VERSION)
+        result shouldBeEqualTo expectedUserAgent
+    }
+
+    @Test
+    fun `given a null app version when computing user agent then returns user agent with a fallback app version`() {
+        // Given
+        givenAppName(AN_APP_NAME)
+        givenAppVersion(null)
+
+        // When
+        val result = computeUserAgentUseCase.execute(context, A_FLAVOUR)
+
+        // Then
+        val expectedUserAgent = constructExpectedUserAgent(AN_APP_NAME, ComputeUserAgentUseCase.FALLBACK_APP_VERSION)
+        result shouldBeEqualTo expectedUserAgent
+    }
+
+    private fun constructExpectedUserAgent(appName: String, appVersion: String): String {
+        return buildString {
+            append(appName)
+            append("/")
+            append(appVersion)
+            append(" (")
+            append(Build.MANUFACTURER)
+            append(" ")
+            append(Build.MODEL)
+            append("; ")
+            append("Android ")
+            append(Build.VERSION.RELEASE)
+            append("; ")
+            append(Build.DISPLAY)
+            append("; ")
+            append("Flavour ")
+            append(A_FLAVOUR)
+            append("; ")
+            append("MatrixAndroidSdk2 ")
+            append(BuildConfig.SDK_VERSION)
+            append(")")
+        }
+    }
+
+    private fun givenAppName(deviceName: String?) {
+        if (deviceName == null) {
+            every { packageManager.getApplicationLabel(any()) } throws Exception("Cannot retrieve application name")
+        } else if (!deviceName.matches("\\A\\p{ASCII}*\\z".toRegex())) {
+            every { packageManager.getApplicationLabel(any()) } returns A_PACKAGE_NAME
+        } else {
+            every { packageManager.getApplicationLabel(any()) } returns deviceName
+        }
+    }
+
+    private fun givenAppVersion(appVersion: String?) {
+        packageInfo.versionName = appVersion
+    }
+}