test: migrate unit tests from JUnit 4 to JUnit 6 (#6276)

JUnit 4 is in maintenance mode, and 4.13.2 (February 2021) is its last
release. Move the unit tests to JUnit Jupiter 6.1.3: the JUnit BOM,
junit-jupiter and the Platform launcher replace junit:junit, and the
unit test tasks run on the JUnit Platform. The test sources change only
mechanically: imports, lifecycle annotations, TemporaryFolder to
@TempDir, and the message argument moved last in three assertions.

Jupiter skips an invalid @Test method, such as one that returns a
value, with only a warning, where JUnit 4 failed the run. Treat
discovery warnings as failures to keep that behavior.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

V2rayNG/app/build.gradle.kts

@@ -149,6 +149,17 @@ android {
         }
     }
 
+    testOptions {
+        unitTests.all {
+            it.useJUnitPlatform()
+            // Treat Jupiter discovery warnings as failures: JUnit 4 failed on an invalid @Test
+            // method, such as one that returns a value, while Jupiter only warns and skips it.
+            // The key is @API(status = EXPERIMENTAL) in JUnit 6; after a JUnit upgrade, check
+            // that a temporary `@Test fun probe() = 1` still fails the unit test task.
+            it.systemProperty("junit.platform.discovery.issue.severity.critical", "WARNING")
+        }
+    }
+
 }
 
 dependencies {
@@ -201,7 +212,9 @@ dependencies {
     implementation(libs.reorderable)
 
     // Testing Libraries
-    testImplementation(libs.junit)
+    testImplementation(platform(libs.junit.bom))
+    testImplementation(libs.junit.jupiter)
+    testRuntimeOnly(libs.junit.platform.launcher)
     androidTestImplementation(libs.androidx.junit)
     androidTestImplementation(libs.androidx.espresso.core)
     testImplementation(libs.mockito.core)

V2rayNG/app/src/test/java/com/v2ray/ang/HttpUtilTest.kt

@@ -1,8 +1,8 @@
 package com.v2ray.ang
 
 import com.v2ray.ang.util.HttpUtil
-import org.junit.Assert.assertEquals
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
 
 class HttpUtilTest {
 

V2rayNG/app/src/test/java/com/v2ray/ang/UtilsTest.kt

@@ -1,10 +1,10 @@
 package com.v2ray.ang
 
 import com.v2ray.ang.util.Utils
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertTrue
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
 
 /**
  * Example local unit test, which will execute on the development machine (host).

V2rayNG/app/src/test/java/com/v2ray/ang/extension/ListExtTest.kt

@@ -1,9 +1,9 @@
 package com.v2ray.ang.extension
 
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertTrue
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
 
 class ListExtTest {
 

V2rayNG/app/src/test/java/com/v2ray/ang/fmt/ShadowsocksFmtTest.kt

@@ -4,14 +4,14 @@ import android.util.Base64
 import android.util.Log
 import com.v2ray.ang.enums.EConfigType
 import com.v2ray.ang.dto.entities.ProfileItem
-import org.junit.After
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertNotNull
-import org.junit.Assert.assertNull
-import org.junit.Assert.assertTrue
-import org.junit.Before
-import org.junit.Test
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertNotNull
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
 import org.mockito.MockedStatic
 import org.mockito.Mockito
 import org.mockito.Mockito.mockStatic
@@ -67,7 +67,7 @@ class ShadowsocksFmtTest {
         return "$SS_SCHEME${base64Encoded}#${remarks.replace(" ", "%20")}"
     }
 
-    @Before
+    @BeforeEach
     fun setUp() {
         mockLog = mockStatic(Log::class.java, Mockito.RETURNS_DEFAULTS)
 
@@ -113,7 +113,7 @@ class ShadowsocksFmtTest {
         }
     }
 
-    @After
+    @AfterEach
     fun tearDown() {
         mockLog.close()
         mockBase64.close()
@@ -271,7 +271,7 @@ class ShadowsocksFmtTest {
         val uri = ShadowsocksFmt.toUri(config)
 
         // Verify URI does not include scheme (toUri returns without ss:// prefix)
-        assertFalse("toUri should not include scheme prefix", uri.startsWith(SS_SCHEME))
+        assertFalse(uri.startsWith(SS_SCHEME), "toUri should not include scheme prefix")
 
         assertTrue(uri.contains("@example.com:8388"))
         assertTrue(uri.contains("#Test%20Server"))
@@ -317,8 +317,8 @@ class ShadowsocksFmtTest {
 
         // Verify toUri returns without scheme, so we need to prepend it
         assertFalse(
-            "toUri should return URI without scheme",
-            regeneratedUri.startsWith(SS_SCHEME)
+            regeneratedUri.startsWith(SS_SCHEME),
+            "toUri should return URI without scheme"
         )
 
         val reparsed = ShadowsocksFmt.parse("$SS_SCHEME$regeneratedUri")
@@ -362,7 +362,7 @@ class ShadowsocksFmtTest {
 
             val result = ShadowsocksFmt.parseSip002(ssUrl)
 
-            assertNotNull("Failed for method: $method", result)
+            assertNotNull(result, "Failed for method: $method")
             assertEquals(method, result?.method)
         }
     }

V2rayNG/app/src/test/java/com/v2ray/ang/handler/OrphanProfileCleanerTest.kt

@@ -1,9 +1,9 @@
 package com.v2ray.ang.handler
 
 import com.v2ray.ang.AppConfig.DEFAULT_SUBSCRIPTION_ID
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertNull
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Test
 
 class OrphanProfileCleanerTest {
 

V2rayNG/app/src/test/java/com/v2ray/ang/handler/ProfileReplacementTest.kt

@@ -2,9 +2,9 @@ package com.v2ray.ang.handler
 
 import com.v2ray.ang.dto.entities.ProfileItem
 import com.v2ray.ang.enums.EConfigType
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertNull
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Test
 
 class ProfileReplacementTest {
 

V2rayNG/app/src/test/java/com/v2ray/ang/handler/SubscriptionIndexTest.kt

@@ -4,10 +4,10 @@ import android.util.Log
 import com.tencent.mmkv.MMKV
 import com.v2ray.ang.dto.entities.SubscriptionItem
 import com.v2ray.ang.util.JsonUtil
-import org.junit.Assert.assertEquals
-import org.junit.Before
-import org.junit.BeforeClass
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
 import org.mockito.Mockito.mockStatic
 import org.mockito.kotlin.any
 import org.mockito.kotlin.mock
@@ -20,7 +20,7 @@ class SubscriptionIndexTest {
     private val mainValues = mutableMapOf<String, String>()
     private val subValues = mutableMapOf<String, String>()
 
-    @Before
+    @BeforeEach
     fun prepareStorage() {
         for ((storage, values) in listOf(main to mainValues, subs to subValues)) {
             reset(storage)
@@ -99,7 +99,7 @@ class SubscriptionIndexTest {
         private val subs: MMKV = mock()
         private val settings: MMKV = mock()
 
-        @BeforeClass
+        @BeforeAll
         @JvmStatic
         fun initializeHandles() {
             mockStatic(MMKV::class.java).use {

V2rayNG/app/src/test/java/com/v2ray/ang/root/RootProcessRunnerTest.kt

@@ -1,7 +1,7 @@
 package com.v2ray.ang.root
 
-import org.junit.Assert.*
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
 import java.util.concurrent.TimeUnit
 
 class RootProcessRunnerTest {

V2rayNG/app/src/test/java/com/v2ray/ang/root/RootProxyManagerTest.kt

@@ -1,7 +1,7 @@
 package com.v2ray.ang.root
 
-import org.junit.Assert.assertEquals
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
 
 class RootProxyManagerTest {
 

V2rayNG/app/src/test/java/com/v2ray/ang/service/DialerWebviewServiceTest.kt

@@ -6,12 +6,12 @@ import android.os.Looper
 import android.webkit.WebSettings
 import android.webkit.WebView
 import android.webkit.WebViewClient
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertSame
-import org.junit.Assert.assertThrows
-import org.junit.Assert.assertTrue
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertSame
+import org.junit.jupiter.api.Assertions.assertThrows
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
 import org.mockito.Mockito.mockConstruction
 import org.mockito.Mockito.mockStatic
 import org.mockito.kotlin.any

V2rayNG/app/src/test/java/com/v2ray/ang/service/RealPingExecutionLimiterTest.kt

@@ -5,9 +5,9 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.async
 import kotlinx.coroutines.awaitAll
 import kotlinx.coroutines.runBlocking
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertTrue
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicInteger

V2rayNG/app/src/test/java/com/v2ray/ang/ui/ScannerActivityTest.kt

@@ -6,8 +6,8 @@ import com.google.zxing.DecodeHintType
 import com.google.zxing.MultiFormatReader
 import com.google.zxing.common.HybridBinarizer
 import com.google.zxing.qrcode.QRCodeWriter
-import org.junit.Assert.assertEquals
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
 import java.nio.ByteBuffer
 
 class ScannerActivityTest {

V2rayNG/app/src/test/java/com/v2ray/ang/ui/apppicker/AppPickerViewModelTest.kt

@@ -1,8 +1,8 @@
 package com.v2ray.ang.ui.apppicker
 
 import android.app.Application
-import org.junit.Assert.assertEquals
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
 import org.mockito.kotlin.mock
 
 class AppPickerViewModelTest {

V2rayNG/app/src/test/java/com/v2ray/ang/ui/logcat/LogcatEntryTest.kt

@@ -1,8 +1,8 @@
 package com.v2ray.ang.ui.logcat
 
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertTrue
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
 
 class LogcatEntryTest {
     @Test

V2rayNG/app/src/test/java/com/v2ray/ang/ui/main/MainImportMenuTest.kt

@@ -1,7 +1,7 @@
 package com.v2ray.ang.ui.main
 
-import org.junit.Assert.assertEquals
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
 
 class MainImportMenuTest {
 

V2rayNG/app/src/test/java/com/v2ray/ang/ui/main/MainTestRequestsTest.kt

@@ -1,11 +1,11 @@
 package com.v2ray.ang.ui.main
 
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertNotEquals
-import org.junit.Assert.assertNull
-import org.junit.Assert.assertTrue
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertNotEquals
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
 
 class MainTestRequestsTest {
     @Test

V2rayNG/app/src/test/java/com/v2ray/ang/ui/main/ServerDeleteTargetTest.kt

@@ -1,9 +1,9 @@
 package com.v2ray.ang.ui.main
 
 import androidx.compose.runtime.saveable.SaverScope
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertNull
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Test
 
 class ServerDeleteTargetTest {
     @Test

V2rayNG/app/src/test/java/com/v2ray/ang/ui/server/ProxyChainMembersTest.kt

@@ -1,8 +1,8 @@
 package com.v2ray.ang.ui.server
 
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertSame
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertSame
+import org.junit.jupiter.api.Test
 
 class ProxyChainMembersTest {
     @Test

V2rayNG/app/src/test/java/com/v2ray/ang/ui/settings/SettingsViewModelTest.kt

@@ -7,10 +7,10 @@ import android.content.pm.PackageManager
 import android.provider.Settings
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.runBlocking
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertTrue
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
 import org.mockito.Mockito.mockConstruction
 import org.mockito.kotlin.mock
 import org.mockito.kotlin.whenever

V2rayNG/app/src/test/java/com/v2ray/ang/ui/userasset/UserAssetViewModelTest.kt

@@ -4,9 +4,9 @@ import android.app.Application
 import com.v2ray.ang.AppConfig
 import com.v2ray.ang.dto.entities.AssetUrlCache
 import com.v2ray.ang.dto.entities.AssetUrlItem
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertTrue
-import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
 import org.mockito.Mockito.mock
 
 class UserAssetViewModelTest {

V2rayNG/app/src/test/java/com/v2ray/ang/util/ZipUtilTest.kt

@@ -1,12 +1,11 @@
 package com.v2ray.ang.util
 
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertThrows
-import org.junit.Assert.assertTrue
-import org.junit.Rule
-import org.junit.Test
-import org.junit.rules.TemporaryFolder
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertThrows
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.io.TempDir
 import java.io.File
 import java.util.zip.ZipEntry
 import java.util.zip.ZipException
@@ -14,13 +13,13 @@ import java.util.zip.ZipOutputStream
 
 class ZipUtilTest {
 
-    @get:Rule
-    val temporaryFolder = TemporaryFolder()
+    @TempDir
+    lateinit var tempDir: File
 
     @Test
     fun unzipToFolderExtractsNestedFile() {
         val archive = createArchive("nested/config" to "value".toByteArray())
-        val destination = File(temporaryFolder.root, "destination")
+        val destination = File(tempDir, "destination")
 
         assertTrue(ZipUtil.unzipToFolder(archive, destination.absolutePath))
         assertEquals("value", File(destination, "nested/config").readText())
@@ -29,7 +28,7 @@ class ZipUtilTest {
     @Test
     fun extractArchiveRejectsPathTraversal() {
         val archive = createArchive("../outside" to "overwrite".toByteArray())
-        val outside = File(temporaryFolder.root, "outside")
+        val outside = File(tempDir, "outside")
 
         assertArchiveRejected(archive)
 
@@ -100,7 +99,7 @@ class ZipUtilTest {
         archive: File,
         limits: ZipUtil.ExtractionLimits = extractionLimits(),
     ) {
-        val destination = File(temporaryFolder.root, "destination")
+        val destination = File(tempDir, "destination")
         assertThrows(ZipException::class.java) {
             ZipUtil.extractArchive(archive, destination, limits)
         }
@@ -108,7 +107,7 @@ class ZipUtilTest {
     }
 
     private fun createArchive(vararg entries: Pair<String, ByteArray>): File {
-        val archive = temporaryFolder.newFile()
+        val archive = File.createTempFile("archive", ".zip", tempDir)
         ZipOutputStream(archive.outputStream()).use { output ->
             entries.forEach { (name, contents) ->
                 output.putNextEntry(ZipEntry(name))

V2rayNG/gradle/libs.versions.toml

@@ -4,7 +4,7 @@ desugarJdkLibs = "2.1.5"
 gradleLicensePlugin = "0.9.91"
 kotlin = "2.4.20"
 coreKtx = "1.19.0"
-junit = "4.13.2"
+junit = "6.1.3"
 junitVersion = "1.3.0"
 espressoCore = "3.7.0"
 activity = "1.13.0"
@@ -26,7 +26,9 @@ coil = "3.6.3"
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
 desugar-jdk-libs = { module = "com.android.tools:desugar_jdk_libs", version.ref = "desugarJdkLibs" }
 gradle-license-plugin = { module = "com.jaredsburrows:gradle-license-plugin", version.ref = "gradleLicensePlugin" }
-junit = { group = "junit", name = "junit", version.ref = "junit" }
+junit-bom = { group = "org.junit", name = "junit-bom", version.ref = "junit" }
+junit-jupiter = { group = "org.junit.jupiter", name = "junit-jupiter" }
+junit-platform-launcher = { group = "org.junit.platform", name = "junit-platform-launcher" }
 androidx-junit = { group = "androidx.test.ext", name = "junit", version.ref = "junitVersion" }
 androidx-espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "espressoCore" }
 mmkv-static = { module = "com.tencent:mmkv-static", version.ref = "mmkvStatic" }