Merge pull request #9177 from sjrd/make-assert-util-friendly-to-scala…

…-js-again Move reflection-related utils from AssertUtil to new ReflectUtil.
scala · Aug 25, 2020 · 7b85389 · 7b85389
2 parents 8329196 + 364b901
commit 7b85389
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Showing 4 changed files with 45 additions and 15 deletions.
diff --git a/src/testkit/scala/tools/testkit/AssertUtil.scala b/src/testkit/scala/tools/testkit/AssertUtil.scala
@@ -31,6 +31,12 @@ import java.util.IdentityHashMap
 
 /** This module contains additional higher-level assert statements
  *  that are ultimately based on junit.Assert primitives.
+ *
+ *  Avoid adding methods, and above all *fields* (including `lazy val`s), that
+ *  require JVM-specific features such as run-time reflection. Otherwise, all
+ *  tests using this object stop working in Scala.js. Put such methods in
+ *  `ReflectUtil` instead. (`ClassTag`s are fine; they are supported in
+ *  Scala.js and Scala Native.)
  */
 object AssertUtil {
 
@@ -263,18 +269,6 @@ object AssertUtil {
   def readyOrNot(awaitable: Awaitable[_]): Boolean = Try(Await.ready(awaitable, TestDuration.Standard)).isSuccess
 
   def withoutATrace[A](body: => A) = NoTrace(body)
-
-  private lazy val modsField = classOf[Field].getDeclaredField("modifiers").tap(_.setAccessible(true))
-
-  def getFieldAccessible[T: ClassTag](n: String): Field =
-    implicitly[ClassTag[T]]
-      .runtimeClass.getDeclaredField(n)
-      .tap { f =>
-        if ((f.getModifiers & Modifier.FINAL) != 0)
-          modsField.setInt(f, f.getModifiers() & ~Modifier.FINAL)
-        if ((f.getModifiers & Modifier.PUBLIC) == 0)
-          f.setAccessible(true)
-      }
 }
 
 object TestDuration {
@@ -309,7 +303,7 @@ class NoTrace[A](body: => A) extends Runnable {
 
   private final val noError = None: Option[Throwable]
 
-  def asserted: Option[Throwable] = 
+  def asserted: Option[Throwable] =
     errors.collect { case (_, e: AssertionError) => e }
       .foldLeft(noError)((res, e) => res.map(suppress(_, e)).orElse(Some(e)))
 

diff --git a/src/testkit/scala/tools/testkit/ReflectUtil.scala b/src/testkit/scala/tools/testkit/ReflectUtil.scala
@@ -0,0 +1,36 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package scala.tools.testkit
+
+import scala.reflect.ClassTag
+import scala.util.chaining._
+import java.lang.reflect.{Array => _, _}
+
+/** This module contains reflection-related utilities.
+ *
+ *  This object contains methods that will not work on Scala.js nor Scala
+ *  Native, making any test using `ReflectUtil` JVM-only.
+ */
+object ReflectUtil {
+  private lazy val modsField = classOf[Field].getDeclaredField("modifiers").tap(_.setAccessible(true))
+
+  def getFieldAccessible[T: ClassTag](n: String): Field =
+    implicitly[ClassTag[T]]
+      .runtimeClass.getDeclaredField(n)
+      .tap { f =>
+        if ((f.getModifiers & Modifier.FINAL) != 0)
+          modsField.setInt(f, f.getModifiers() & ~Modifier.FINAL)
+        if ((f.getModifiers & Modifier.PUBLIC) == 0)
+          f.setAccessible(true)
+      }
+}
diff --git a/test/junit/scala/collection/immutable/IntMapTest.scala b/test/junit/scala/collection/immutable/IntMapTest.scala
@@ -17,7 +17,7 @@ import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
 
-import scala.tools.testkit.AssertUtil.{getFieldAccessible => f}
+import scala.tools.testkit.ReflectUtil.{getFieldAccessible => f}
 
 @RunWith(classOf[JUnit4])
 class IntMapTest {

diff --git a/test/junit/scala/collection/immutable/LongMapTest.scala b/test/junit/scala/collection/immutable/LongMapTest.scala
@@ -17,7 +17,7 @@ import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
 
-import scala.tools.testkit.AssertUtil.{getFieldAccessible => f}
+import scala.tools.testkit.ReflectUtil.{getFieldAccessible => f}
 
 @RunWith(classOf[JUnit4])
 class LongMapTest {