Add unit test for main method discovery

6 files changed, 58 insertions, 9 deletions

diff --git a/scalalib/test/resources/hello-world-no-main/core/src-2.10/Shim.scala b/scalalib/test/resources/hello-world-no-main/core/src-2.10/Shim.scala
new file mode 100644
index 00000000..025cff5c
--- /dev/null
+++ b/scalalib/test/resources/hello-world-no-main/core/src-2.10/Shim.scala
@@ -0,0 +1,5 @@
+object Shim{
+  def main(args: Array[String]): Unit = {
+    Main0(args(0), scala.util.Properties.versionNumberString + " rox")
+  }
+}
\ No newline at end of file
diff --git a/scalalib/test/resources/hello-world-no-main/core/src-2.11/Shim.scala b/scalalib/test/resources/hello-world-no-main/core/src-2.11/Shim.scala
new file mode 100644
index 00000000..d98a6de1
--- /dev/null
+++ b/scalalib/test/resources/hello-world-no-main/core/src-2.11/Shim.scala
@@ -0,0 +1,5 @@
+object Shim{
+  def main(args: Array[String]): Unit = {
+    Main0(args(0), scala.util.Properties.versionNumberString + " pwns")
+  }
+}
\ No newline at end of file
diff --git a/scalalib/test/resources/hello-world-no-main/core/src-2.12/Shim.scala b/scalalib/test/resources/hello-world-no-main/core/src-2.12/Shim.scala
new file mode 100644
index 00000000..1f3e1c0f
--- /dev/null
+++ b/scalalib/test/resources/hello-world-no-main/core/src-2.12/Shim.scala
@@ -0,0 +1,5 @@
+object Shim{
+  def main(args: Array[String]): Unit = {
+    Main0(args(0), scala.util.Properties.versionNumberString + " leet")
+  }
+}
\ No newline at end of file
diff --git a/scalalib/test/resources/hello-world-no-main/core/src/Main.scala b/scalalib/test/resources/hello-world-no-main/core/src/Main.scala
new file mode 100644
index 00000000..5f68fd3f
--- /dev/null
+++ b/scalalib/test/resources/hello-world-no-main/core/src/Main.scala
@@ -0,0 +1,11 @@
+import scala.collection._
+import java.nio.file.{Files, Paths}
+
+import Main.{args, greeting}
+object Main0{
+  def apply(s: String, greeting: String) = {
+    val resultPath = Paths.get(s)
+    Files.createDirectories(resultPath.getParent)
+    Files.write(resultPath, greeting.getBytes)
+  }
+}
diff --git a/scalalib/test/resources/hello-world-no-main/core/src/Result.scala b/scalalib/test/resources/hello-world-no-main/core/src/Result.scala
new file mode 100644
index 00000000..d7d29a51
--- /dev/null
+++ b/scalalib/test/resources/hello-world-no-main/core/src/Result.scala
@@ -0,0 +1,7 @@
+object Person {
+  def fromString(s: String): Person = {
+    val Array(name, age) = s.split(":")
+    Person(name, age.toInt)
+  }
+}
+case class Person(name: String, age: Int)
diff --git a/scalalib/test/src/mill/scalalib/HelloWorldTests.scala b/scalalib/test/src/mill/scalalib/HelloWorldTests.scala
index 945bec27..7a788b1f 100644
--- a/scalalib/test/src/mill/scalalib/HelloWorldTests.scala
+++ b/scalalib/test/src/mill/scalalib/HelloWorldTests.scala
@@ -122,7 +122,7 @@ object HelloWorldTests extends TestSuite {
     "Person$.class"
   )
 
-  def workspaceTest[T, M <: TestUtil.BaseModule: Discover](m: M)
+  def workspaceTest[T, M <: TestUtil.BaseModule: Discover](m: M, resourcePath: Path = resourcePath)
                                                          (t: TestEvaluator[M] => T)
                                                          (implicit tp: TestPath): T = {
     val eval = new TestEvaluator(m)
@@ -300,11 +300,27 @@ object HelloWorldTests extends TestSuite {
           read(runResult) == "hello rockjam, your age is: 25"
         )
       }
-      'notRunWithoutMainClass - workspaceTest(HelloWorldWithoutMain){eval =>
-        val Left(Result.Exception(err, _)) = eval.apply(HelloWorldWithoutMain.core.run())
+      'notRunWithoutMainClass - workspaceTest(
+        HelloWorldWithoutMain,
+        pwd / 'scalalib / 'test / 'resources / "hello-world-no-main"
+      ){eval =>
+        val Left(Result.Failure(_, None)) = eval.apply(HelloWorldWithoutMain.core.run())
+      }
+
+      'runDiscoverMainClass - workspaceTest(HelloWorldWithoutMain){eval =>
+        // Make sure even if there isn't a main class defined explicitly, it gets
+        // discovered by Zinc and used
+        val runResult = eval.outPath / 'core / 'run / 'dest / "hello-mill"
+        val Right((_, evalCount)) = eval.apply(
+          HelloWorldWithoutMain.core.run(runResult.toString)
+        )
+
+        assert(evalCount > 0)
+
 
         assert(
-          err.isInstanceOf[RuntimeException]
+          exists(runResult),
+          read(runResult) == "hello rockjam, your age is: 25"
         )
       }
     }
@@ -337,12 +353,12 @@ object HelloWorldTests extends TestSuite {
           read(runResult) == "hello rockjam, your age is: 25"
         )
       }
-      'notRunWithoutMainClass - workspaceTest(HelloWorldWithoutMain){eval =>
-        val Left(Result.Exception(err, _)) = eval.apply(HelloWorldWithoutMain.core.runLocal())
+      'notRunWithoutMainClass - workspaceTest(
+        HelloWorldWithoutMain,
+        pwd / 'scalalib / 'test / 'resources / "hello-world-no-main"
+      ){eval =>
+        val Left(Result.Failure(_, None)) = eval.apply(HelloWorldWithoutMain.core.runLocal())
 
-        assert(
-          err.isInstanceOf[RuntimeException]
-        )
       }
     }
     'jar - {