Simplify snapshot test infrastructure

With only MinimizedSnapshotScipGenerator remaining, the abstraction
layers became unnecessary:

- Inline AggregateSnapshotGenerator into SaveSnapshots and delete it
- Inline the abstract SnapshotSuite into its only subclass
- Drop SnapshotHandler.withoutFinishedEvent (only used by the dropped
  aggregator)
- Drop a dead onFinished override in MinimizedSnapshotScipGenerator

Author: jupblb

tests/snapshots/src/main/scala/tests/AggregateSnapshotGenerator.scala

@@ -20,7 +20,6 @@ class MinimizedSnapshotScipGenerator extends SnapshotGenerator {
     val exit = ScipJava.app.run(args)
     require(exit == 0)
   }
-  def onFinished(context: SnapshotContext): Unit = ()
   override def run(context: SnapshotContext, handler: SnapshotHandler): Unit = {
     onTargetroot(
       context,

tests/snapshots/src/main/scala/tests/MinimizedSnapshotScipGenerator.scala

@@ -2,19 +2,11 @@ package tests
 
 object SaveSnapshots {
   def main(args: Array[String]): Unit = {
-    val expectDirectory = tests.snapshots.BuildInfo.snapshotDirectory.toPath
-    val mapping = Map(
-      "minimized" -> new MinimizedSnapshotScipGenerator()
+    val context = SnapshotContext(
+      tests.snapshots.BuildInfo.snapshotDirectory.toPath
     )
-
-    val enabledGenerators =
-      if (args.isEmpty)
-        mapping.values.toList
-      else
-        args.flatMap(mapping.get).toList
-
-    val generator = new AggregateSnapshotGenerator(enabledGenerators)
-
-    generator.run(SnapshotContext(expectDirectory), new SaveSnapshotHandler)
+    val handler = new SaveSnapshotHandler
+    new MinimizedSnapshotScipGenerator().run(context, handler)
+    handler.onFinished(context)
   }
 }

tests/snapshots/src/main/scala/tests/SaveSnapshots.scala

@@ -3,22 +3,10 @@ package tests
 import java.nio.file.Path
 
 abstract class SnapshotHandler {
-  self =>
   def onSnapshotTest(
       context: SnapshotContext,
       expectFile: Path,
       obtainedOutput: () => String
   ): Unit = ()
   def onFinished(context: SnapshotContext): Unit = ()
-  final def withoutFinishedEvent: SnapshotHandler =
-    new SnapshotHandler {
-      override def onFinished(context: SnapshotContext): Unit = () // Do nothing
-      override def onSnapshotTest(
-          context: SnapshotContext,
-          expectFile: Path,
-          obtainedOutput: () => String
-      ): Unit = {
-        self.onSnapshotTest(context, expectFile, obtainedOutput)
-      }
-    }
 }

tests/snapshots/src/main/scala/tests/SnapshotHandler.scala

@@ -2,14 +2,9 @@ package tests
 
 import munit.FunSuite
 
-abstract class SnapshotSuite(generator: SnapshotGenerator)
-    extends FunSuite
-    with AssertSnapshotHandlers {
-  generator.run(
+class MinimizedSnapshotScipSuite extends FunSuite with AssertSnapshotHandlers {
+  new MinimizedSnapshotScipGenerator().run(
     SnapshotContext(tests.snapshots.BuildInfo.snapshotDirectory.toPath),
     new AssertSnapshotHandler
   )
 }
-
-class MinimizedSnapshotScipSuite
-    extends SnapshotSuite(new MinimizedSnapshotScipGenerator)