1 files changed, 95 insertions, 0 deletions
diff --git a/main/test/src/eval/TaskTests.scala b/main/test/src/eval/TaskTests.scala
new file mode 100644
index 00000000..0bfd8efc
--- /dev/null
+++ b/main/test/src/eval/TaskTests.scala
@@ -0,0 +1,95 @@
+package mill.eval
+
+import utest._
+
+import mill.T
+
+import mill.util.TestEvaluator
+object TaskTests extends TestSuite{
+  val tests = Tests{
+    object build extends mill.util.TestUtil.BaseModule{
+      var count = 0
+      // Explicitly instantiate `Function1` objects to make sure we get
+      // different instances each time
+      def staticWorker = T.worker{
+        new Function1[Int, Int] {
+          def apply(v1: Int) = v1 + 1
+        }
+      }
+      def noisyWorker = T.worker{
+        new Function1[Int, Int] {
+          def apply(v1: Int) = input() + 1
+        }
+      }
+      def input = T.input{
+        count += 1
+        count
+      }
+      def task = T.task{
+        count += 1
+        count
+      }
+      def taskInput = T{ input() }
+      def taskNoInput = T{ task() }
+
+      def persistent = T.persistent{
+        input() // force re-computation
+        os.makeDir.all(T.ctx().dest)
+        os.write.append(T.ctx().dest/'count, "hello\n")
+        os.read.lines(T.ctx().dest/'count).length
+      }
+      def nonPersistent = T{
+        input() // force re-computation
+        os.makeDir.all(T.ctx().dest)
+        os.write.append(T.ctx().dest/'count, "hello\n")
+        os.read.lines(T.ctx().dest/'count).length
+      }
+
+      def staticWorkerDownstream = T{
+        staticWorker().apply(1)
+      }
+      def noisyWorkerDownstream = T{
+        noisyWorker().apply(1)
+      }
+    }
+
+    'inputs - {
+      // Inputs always re-evaluate, including forcing downstream cached Targets
+      // to re-evaluate, but normal Tasks behind a Target run once then are cached
+      val check = new TestEvaluator(build)
+
+      val Right((1, 1)) = check.apply(build.taskInput)
+      val Right((2, 1)) = check.apply(build.taskInput)
+      val Right((3, 1)) = check.apply(build.taskInput)
+
+      val Right((4, 1)) = check.apply(build.taskNoInput)
+      val Right((4, 0)) = check.apply(build.taskNoInput)
+      val Right((4, 0)) = check.apply(build.taskNoInput)
+    }
+
+    'persistent - {
+      // Persistent tasks keep the working dir around between runs
+      val check = new TestEvaluator(build)
+      val Right((1, 1)) = check.apply(build.persistent)
+      val Right((2, 1)) = check.apply(build.persistent)
+      val Right((3, 1)) = check.apply(build.persistent)
+
+      val Right((1, 1)) = check.apply(build.nonPersistent)
+      val Right((1, 1)) = check.apply(build.nonPersistent)
+      val Right((1, 1)) = check.apply(build.nonPersistent)
+    }
+
+    'worker - {
+      // Persistent task
+      def check = new TestEvaluator(build)
+
+      val Right((2, 1)) = check.apply(build.noisyWorkerDownstream)
+      val Right((3, 1)) = check.apply(build.noisyWorkerDownstream)
+      val Right((4, 1)) = check.apply(build.noisyWorkerDownstream)
+
+      val Right((2, 1)) = check.apply(build.staticWorkerDownstream)
+      val Right((2, 0)) = check.apply(build.staticWorkerDownstream)
+      val Right((2, 0)) = check.apply(build.staticWorkerDownstream)
+    }
+  }
+}