[2.x] test: Add regression test for resource reading (#9552)

sbt-app/src/sbt-test/tests/resources/build.sbt

@@ -1,3 +1,3 @@
-scalaVersion := "2.12.21"
-val specs = "org.specs2" %% "specs2-core" % "4.3.4"
-libraryDependencies += specs % Test
+scalaVersion := "3.8.4"
+val munit = "org.scalameta" %% "munit" % "1.0.4"
+libraryDependencies += munit % Test

sbt-app/src/sbt-test/tests/resources/src/test/scala/BasicTest.scala

@@ -1,11 +0,0 @@
-import org.specs2.mutable._
-
-object BasicTest extends Specification
-{
-  "Test resource on test classpath" in {
-     getClass.getResource("TestResource.txt") must not beNull
-  }
-  "Main resource on test classpath" in {
-     getClass.getResource("MainResource.txt") must not beNull
-  }
-}

sbt-app/src/sbt-test/tests/resources/src/test/scala/ResourceTest.scala

@@ -0,0 +1,27 @@
+import munit.FunSuite
+
+class ResourceTest extends FunSuite:
+  test("Test resource on test classpath"):
+    assert(getClass.getResource("TestResource.txt") != null)
+
+  test("Test resource with slash on test classpath"):
+    assert(getClass.getResource("/TestResource.txt") != null)
+
+  test("Test resource contents"):
+    val str = new String(
+      getClass.getResourceAsStream("/TestResource.txt").readAllBytes()
+    )
+    assert(str == "Success")
+
+  test("Main resource on test classpath"):
+    assert(getClass.getResource("MainResource.txt") != null)
+
+  test("Main resource with slash on test classpath"):
+    assert(getClass.getResource("/MainResource.txt") != null)
+
+  test("Main resource contents"):
+    val str = new String(
+      getClass.getResourceAsStream("/MainResource.txt").readAllBytes()
+    )
+    assert(str == "Main")
+end ResourceTest