Adopt Burst's new TestInterceptors (#1685)

Co-authored-by: Jesse Wilson <[email protected]>

Author: swankjesse

gradle/libs.versions.toml

@@ -1,4 +1,5 @@
 [versions]
+burst = "2.7.0"
 jmh = "1.37"
 kotlin = "2.2.10"
 ktlint = "0.48.2"
@@ -10,7 +11,8 @@ androidx-test-ext-junit = { module = "androidx.test.ext:junit", version = "1.3.0
 androidx-test-runner = { module = "androidx.test:runner", version = "1.5.2" }
 binaryCompatibilityValidator = { module = "org.jetbrains.kotlinx.binary-compatibility-validator:org.jetbrains.kotlinx.binary-compatibility-validator.gradle.plugin", version = "0.18.1" }
 bnd = { module = "biz.aQute.bnd:biz.aQute.bnd.gradle", version = "7.1.0" }
-burst-gradle-plugin = { module = "app.cash.burst:burst-gradle-plugin", version = "2.7.0" }
+burst-gradle-plugin = { module = "app.cash.burst:burst-gradle-plugin", version.ref = "burst" }
+burst-runtime = { module = "app.cash.burst:burst", version.ref = "burst" }
 dokka = { module = "org.jetbrains.dokka:dokka-gradle-plugin", version = "2.0.0" }
 jmh-core = { module = "org.openjdk.jmh:jmh-core", version.ref = "jmh" }
 jmh-generator = { module = "org.openjdk.jmh:jmh-generator-annprocess", version.ref = "jmh" }

okio-nodefilesystem/build.gradle.kts

@@ -5,6 +5,7 @@ import org.jetbrains.kotlin.gradle.dsl.JsModuleKind
 
 plugins {
   kotlin("multiplatform")
+  id("app.cash.burst")
   id("org.jetbrains.dokka")
   id("com.vanniktech.maven.publish.base")
   id("binary-compatibility-validator")

okio-testing-support/build.gradle.kts

@@ -1,5 +1,6 @@
 plugins {
   kotlin("multiplatform")
+  id("app.cash.burst")
   id("build-support")
 }
 
@@ -17,6 +18,7 @@ kotlin {
       dependencies {
         api(projects.okio)
         api(libs.kotlin.test)
+        api(libs.burst.runtime)
       }
     }
 

okio-testing-support/src/commonMain/kotlin/okio/AbstractFileSystemTest.kt

@@ -15,7 +15,7 @@
  */
 package okio
 
-import kotlin.test.BeforeTest
+import app.cash.burst.InterceptTest
 import kotlin.test.Ignore
 import kotlin.test.Test
 import kotlin.test.assertContentEquals
@@ -43,16 +43,14 @@ abstract class AbstractFileSystemTest(
   val closeBehavior: CloseBehavior,
   temporaryDirectory: Path,
 ) {
-  val base: Path = temporaryDirectory / "${this::class.simpleName}-${randomToken(16)}"
+  @InterceptTest
+  private val baseTestDirectory = TestDirectory(fileSystem, temporaryDirectory)
+  protected val base: Path get() = baseTestDirectory.path
+
   private val isNodeJsFileSystem = fileSystem::class.simpleName?.startsWith("NodeJs") ?: false
   private val isWasiFileSystem = fileSystem::class.simpleName?.startsWith("Wasi") ?: false
   private val isWrappingJimFileSystem = this::class.simpleName?.contains("JimFileSystem") ?: false
 
-  @BeforeTest
-  fun setUp() {
-    fileSystem.createDirectories(base)
-  }
-
   @Test
   fun doesNotExistsWithInvalidPathDoesNotThrow() {
     if (isNodeJsFileSystemOnWindows()) return

okio-testing-support/src/commonMain/kotlin/okio/TestDirectory.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2025 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 okio
+
+import app.cash.burst.TestFunction
+import app.cash.burst.TestInterceptor
+
+/**
+ * A temporary directory on [fileSystem] that's usable for the current test.
+ */
+class TestDirectory(
+  val fileSystem: FileSystem,
+  val temporaryDirectory: Path = FileSystem.SYSTEM_TEMPORARY_DIRECTORY,
+) : TestInterceptor {
+  lateinit var path: Path
+    private set
+
+  override fun intercept(testFunction: TestFunction) {
+    path = temporaryDirectory / "${testFunction.functionName}-${randomToken(16)}"
+    fileSystem.createDirectories(path)
+    testFunction()
+  }
+}

okio-testing-support/src/jvmMain/kotlin/okio/TestExecutor.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2025 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 okio
+
+import app.cash.burst.TestFunction
+import app.cash.burst.TestInterceptor
+import java.util.concurrent.Executors
+import java.util.concurrent.Future
+import java.util.concurrent.ScheduledExecutorService
+import java.util.concurrent.ScheduledFuture
+import java.util.concurrent.ThreadFactory
+import java.util.concurrent.TimeUnit
+import kotlin.time.Duration
+
+/**
+ * Manages a `ExecutorService` and shuts it down after the test.
+ */
+class TestExecutor(
+  private val corePoolSize: Int = 0,
+) : TestInterceptor {
+  lateinit var executorService: ScheduledExecutorService
+    private set
+
+  fun <T> submit(task: () -> T): Future<T> = executorService.submit<T>(task)
+
+  fun <T> schedule(delay: Duration, command: () -> T): ScheduledFuture<T> =
+    executorService.schedule(command, delay.inWholeNanoseconds, TimeUnit.NANOSECONDS)
+
+  override fun intercept(testFunction: TestFunction) {
+    executorService = when {
+      isLoom -> Executors.newScheduledThreadPool(corePoolSize, newVirtualThreadFactory())
+      else -> Executors.newScheduledThreadPool(corePoolSize)
+    }
+    try {
+      testFunction()
+    } finally {
+      executorService.shutdown()
+    }
+  }
+
+  private companion object {
+    val isLoom = System.getProperty("loomEnabled").toBoolean()
+
+    fun newVirtualThreadFactory(): ThreadFactory {
+      val threadBuilder = Thread::class.java.getMethod("ofVirtual").invoke(null)
+      return Class.forName("java.lang.Thread\$Builder").getMethod("factory")
+        .invoke(threadBuilder) as ThreadFactory
+    }
+  }
+}

okio-testing-support/src/jvmMain/kotlin/okio/TestingExecutors.kt

@@ -7,6 +7,7 @@ plugins {
   // TODO: Restore Dokka once this issue is resolved.
   //     https://github.com/Kotlin/dokka/issues/3038
   // id("org.jetbrains.dokka")
+  id("app.cash.burst")
   id("com.vanniktech.maven.publish.base")
   id("build-support")
   id("binary-compatibility-validator")

okio-wasifilesystem/build.gradle.kts

@@ -15,7 +15,7 @@
  */
 package okio
 
-import kotlin.test.BeforeTest
+import app.cash.burst.InterceptTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith
@@ -29,15 +29,14 @@ import okio.Path.Companion.toPath
  */
 class WasiFileSystemPreopensTest {
   private val fileSystem = WasiFileSystem
-  private val testId = "${this::class.simpleName}-${randomToken(16)}"
-  private val baseA: Path = "/a".toPath() / testId
-  private val baseB: Path = "/b".toPath() / testId
 
-  @BeforeTest
-  fun setUp() {
-    fileSystem.createDirectory(baseA)
-    fileSystem.createDirectory(baseB)
-  }
+  @InterceptTest
+  private val testDirectoryA = TestDirectory(fileSystem, "/a".toPath())
+  private val baseA: Path get() = testDirectoryA.path
+
+  @InterceptTest
+  private val testDirectoryB = TestDirectory(fileSystem, "/b".toPath())
+  private val baseB: Path get() = testDirectoryB.path
 
   @Test
   fun operateOnPreopens() {
@@ -75,7 +74,7 @@ class WasiFileSystemPreopensTest {
 
   @Test
   fun cannotOperateOutsideOfPreopens() {
-    val noPreopen = "/c".toPath() / testId
+    val noPreopen = "/c/absent".toPath()
     assertFailsWith<FileNotFoundException> {
       fileSystem.createDirectory(noPreopen)
     }

okio-wasifilesystem/src/wasmWasiTest/kotlin/okio/WasiFileSystemPreopensTest.kt

@@ -15,7 +15,7 @@
  */
 package okio
 
-import kotlin.test.BeforeTest
+import app.cash.burst.InterceptTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith
@@ -25,12 +25,10 @@ import okio.Path.Companion.toPath
 
 class WasiTest {
   private val fileSystem = WasiFileSystem
-  private val base: Path = "/tmp".toPath() / "${this::class.simpleName}-${randomToken(16)}"
 
-  @BeforeTest
-  fun setUp() {
-    fileSystem.createDirectory(base)
-  }
+  @InterceptTest
+  private val testDirectory = TestDirectory(fileSystem, "/tmp".toPath())
+  private val base: Path get() = testDirectory.path
 
   @Test
   fun createDirectory() {