Test --cross with the package sub-command

Author: Gedochao

modules/integration/src/test/scala/scala/cli/integration/PackageTestDefinitions.scala

@@ -1354,7 +1354,7 @@ abstract class PackageTestDefinitions extends ScalaCliSuite with TestScalaVersio
             )
             else Nil)
       packageDescription = packageOpts.headOption.getOrElse("bootstrap")
-    }
+    } {
       test(s"package with main method in test scope ($packageDescription)") {
         val mainClass         = "TestScopeMain"
         val testScopeFileName = s"$mainClass.test.scala"
@@ -1388,5 +1388,46 @@ abstract class PackageTestDefinitions extends ScalaCliSuite with TestScalaVersio
           expect(output == message)
         }
       }
+
+      if (actualScalaVersion == Constants.scala3Next)
+        test(s"package ($packageDescription, --cross)") {
+          val crossDirective =
+            s"//> using scala $actualScalaVersion ${Constants.scala213} ${Constants.scala212}"
+          val mainClass  = "TestScopeMain"
+          val mainFile   = s"$mainClass.scala"
+          val message    = "Hello"
+          val outputFile = mainClass + extension
+          TestInputs(
+            os.rel / "Messages.scala" ->
+              s"""$crossDirective
+                 |object Messages { val msg = "$message" }""".stripMargin,
+            os.rel / mainFile ->
+              s"""object $mainClass extends App { println(Messages.msg) }""".stripMargin
+          ).fromRoot { root =>
+            os.proc(
+              TestUtil.cli,
+              "--power",
+              "package",
+              "--cross",
+              extraOptions,
+              ".",
+              packageOpts
+            )
+              .call(cwd = root)
+            val outputFilePath = root / outputFile
+            expect(os.isFile(outputFilePath))
+            val output =
+              if (packageDescription == libraryArg)
+                os.proc(TestUtil.cli, "run", outputFilePath).call(cwd = root).out.trim()
+              else if (packageDescription == jsArg)
+                os.proc(node, outputFilePath).call(cwd = root).out.trim()
+              else {
+                expect(Files.isExecutable(outputFilePath.toNIO))
+                TestUtil.maybeUseBash(outputFilePath)(cwd = root).out.trim()
+              }
+            expect(output == message)
+          }
+        }
+    }
   }
 }