1 files changed, 104 insertions, 0 deletions
diff --git a/scalalib/test/src/scalafmt/ScalafmtTests.scala b/scalalib/test/src/scalafmt/ScalafmtTests.scala
new file mode 100644
index 00000000..dcbdb769
--- /dev/null
+++ b/scalalib/test/src/scalafmt/ScalafmtTests.scala
@@ -0,0 +1,104 @@
+package mill.scalalib.scalafmt
+
+import mill.main.Tasks
+import mill.scalalib.ScalaModule
+import mill.util.{TestEvaluator, TestUtil}
+import utest._
+import utest.framework.TestPath
+
+object ScalafmtTests extends TestSuite {
+
+  trait TestBase extends TestUtil.BaseModule {
+    def millSourcePath =
+      TestUtil.getSrcPathBase() / millOuterCtx.enclosing.split('.')
+  }
+
+  object ScalafmtTestModule extends TestBase {
+    object core extends ScalaModule with ScalafmtModule {
+      def scalaVersion = "2.12.4"
+    }
+  }
+
+  val resourcePath = os.pwd / 'scalalib / 'test / 'resources / 'scalafmt
+
+  def workspaceTest[T](
+      m: TestUtil.BaseModule,
+      resourcePath: os.Path = resourcePath)(t: TestEvaluator => T)(
+      implicit tp: TestPath): T = {
+    val eval = new TestEvaluator(m)
+    os.remove.all(m.millSourcePath)
+    os.remove.all(eval.outPath)
+    os.makeDir.all(m.millSourcePath / os.up)
+    os.copy(resourcePath, m.millSourcePath)
+    t(eval)
+  }
+
+  def tests: Tests = Tests {
+    'scalafmt - {
+      def checkReformat(reformatCommand: mill.define.Command[Unit]) =
+        workspaceTest(ScalafmtTestModule) { eval =>
+          val before = getProjectFiles(ScalafmtTestModule.core, eval)
+
+          // first reformat
+          val Right(_) = eval.apply(reformatCommand)
+
+          val firstReformat = getProjectFiles(ScalafmtTestModule.core, eval)
+
+          assert(
+            firstReformat("Main.scala").modifyTime > before("Main.scala").modifyTime,
+            firstReformat("Main.scala").content != before("Main.scala").content,
+            firstReformat("Person.scala").modifyTime > before("Person.scala").modifyTime,
+            firstReformat("Person.scala").content != before("Person.scala").content,
+            // resources files aren't modified
+            firstReformat("application.conf").modifyTime == before(
+              "application.conf").modifyTime
+          )
+
+          // cached reformat
+          val Right(_) = eval.apply(reformatCommand)
+
+          val cached = getProjectFiles(ScalafmtTestModule.core, eval)
+
+          assert(
+            cached("Main.scala").modifyTime == firstReformat("Main.scala").modifyTime,
+            cached("Person.scala").modifyTime == firstReformat("Person.scala").modifyTime,
+            cached("application.conf").modifyTime == firstReformat(
+              "application.conf").modifyTime
+          )
+
+          // reformat after change
+          os.write.over(cached("Main.scala").path,
+                     cached("Main.scala").content + "\n object Foo")
+
+          val Right(_) = eval.apply(reformatCommand)
+
+          val afterChange = getProjectFiles(ScalafmtTestModule.core, eval)
+
+          assert(
+            afterChange("Main.scala").modifyTime > cached("Main.scala").modifyTime,
+            afterChange("Person.scala").modifyTime == cached("Person.scala").modifyTime,
+            afterChange("application.conf").modifyTime == cached(
+              "application.conf").modifyTime
+          )
+        }
+
+      'reformat - checkReformat(ScalafmtTestModule.core.reformat())
+      'reformatAll - checkReformat(
+        ScalafmtModule.reformatAll(Tasks(Seq(ScalafmtTestModule.core.sources))))
+    }
+  }
+
+  case class FileInfo(content: String, modifyTime: Long, path: os.Path)
+
+  def getProjectFiles(m: ScalaModule, eval: TestEvaluator) = {
+    val Right((sources, _)) = eval.apply(m.sources)
+    val Right((resources, _)) = eval.apply(m.resources)
+
+    val sourcesFiles = sources.flatMap(p => os.walk(p.path))
+    val resourcesFiles = resources.flatMap(p => os.walk(p.path))
+    (sourcesFiles ++ resourcesFiles).map { p =>
+      p.last -> FileInfo(os.read(p), os.mtime(p), p)
+    }.toMap
+  }
+
+}