Fix #497 - don't load fixtures for empty test suites (#499)

Previously, MUnit loaded fixtures even for test suites that had no
tests. Now, we skip the entire suite if there are no tests to run.

.tool-versions

@@ -0,0 +1 @@
+nodejs 16.7.0

munit/non-jvm/src/main/scala/org/junit/experimental/categories/Category.scala

@@ -0,0 +1,5 @@
+package org.junit.experimental.categories
+
+import scala.annotation.Annotation
+
+class Category(classes: Array[Class[_]]) extends Annotation

munit/shared/src/main/scala/munit/MUnitRunner.scala

@@ -174,7 +174,7 @@ class MUnitRunner(val cls: Class[_ <: Suite], newInstance: () => Suite)
   }
 
   private def runAll(notifier: RunNotifier): Future[Unit] = {
-    if (PlatformCompat.isIgnoreSuite(cls)) {
+    if (PlatformCompat.isIgnoreSuite(cls) || munitTests.isEmpty) {
       val description = getDescription()
       notifier.fireTestIgnored(description)
       return Future.successful(())

tests/shared/src/main/scala/munit/Issue285FrameworkSuite.scala

@@ -28,7 +28,7 @@ class Issue285FrameworkSuite extends FunSuite {
   }
   test("issue-285-fail") {
     val promise = Promise[Unit]()
-    PlatformCompat.setTimeout(20) {
+    PlatformCompat.setTimeout(40) {
       promise.trySuccess(())
     }
     promise.future

tests/shared/src/main/scala/munit/Issue497FrameworkSuite.scala

@@ -0,0 +1,44 @@
+package munit
+
+import org.junit.experimental.categories.Category
+
+class Slow extends Tag("Slow")
+
+@Category(Array(classOf[Slow]))
+class Issue497FrameworkSuite extends FunSuite {
+  def println(msg: String): Unit = TestingConsole.out.println(msg)
+  val myFixture: Fixture[Unit] = new Fixture[Unit]("myFixture") {
+    def apply(): Unit = println("### myFixture apply() ###")
+
+    override def beforeAll(): Unit = {
+      println("### beforeAll is running ###")
+    }
+
+    override def afterAll(): Unit = {
+      println("### afterAll is running ###")
+    }
+  }
+  override def munitFixtures: List[Fixture[Unit]] = List(myFixture)
+
+  test("test1") {
+    myFixture()
+    assertEquals(1, 1)
+  }
+
+  test("test2") {
+    myFixture()
+    assertEquals(1, 1)
+  }
+}
+
+object Issue497FrameworkSuite
+    extends FrameworkTest(
+      classOf[Issue497FrameworkSuite],
+      """|munit.Issue497FrameworkSuite:
+         |""".stripMargin,
+      arguments = Array("--exclude-categories=munit.Slow"),
+      tags = Set(
+        OnlyJVM
+      ),
+      format = StdoutFormat
+    )

tests/shared/src/test/scala/munit/FrameworkSuite.scala

@@ -29,6 +29,7 @@ class FrameworkSuite extends BaseFrameworkSuite {
     AssertionsFrameworkSuite,
     Issue179FrameworkSuite,
     Issue285FrameworkSuite,
+    Issue497FrameworkSuite,
     ScalaCheckExceptionFrameworkSuite,
     BoxedFrameworkSuite
   )