Write test to check for specialized apply

Author: felixmulder

compiler/test/dotty/tools/dotc/transform/SpecializeFunction1Tests.scala

@@ -29,10 +29,25 @@ class SpecializeFunction1Tests extends DottyBytecodeTest {
       val applys = methods
         .collect {
           case m if m.name == "apply$mcII$sp" => m
+          case m if m.name == "apply" => m
         }
+        .map(_.name)
         .toList
 
-      assert(applys.length == 1, "Wrong number of specialized applys")
+      assert(
+        // there should be two "apply", one generic and the one overwritten and
+        // then the specialized one
+        applys.length == 3,
+        s"Wrong number of specialized applys, actual length: ${applys.length} $applys"
+      )
+      assert(
+        applys.contains("apply"),
+        "Foo did not contain `apply` forwarder method"
+      )
+      assert(
+        applys.contains("apply$mcII$sp"),
+        "Foo did not contain specialized apply"
+      )
     }
   }
 }