Initial pass at engine.#Scratch - failing

Signed-off-by: Joel Longtine <joel@dagger.io>

tests/tasks.bats

@@ -88,3 +88,8 @@ setup() {
 
     "$DAGGER" --europa up ./build_auth.cue
 }
+@test "task: #Scratch" {
+    cd "$TESTDIR"/tasks/scratch
+    "$DAGGER" --europa up ./scratch.cue -l debug
+}
+

tests/tasks/scratch/cue.mod/module.cue

@@ -0,0 +1 @@
+module: ""

tests/tasks/scratch/cue.mod/pkg/.gitignore

@@ -0,0 +1,3 @@
+# generated by dagger
+alpha.dagger.io
+dagger.lock

tests/tasks/scratch/scratch.cue

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"alpha.dagger.io/europa/dagger/engine"
+)
+
+engine.#Plan & {
+	actions: {
+		image: engine.#Pull & {
+			source: "alpine:3.15.0@sha256:e7d88de73db3d3fd9b2d63aa7f447a10fd0220b7cbf39803c803f2af9ba256b3"
+		}
+
+		scratch: engine.#Scratch
+
+		exec: engine.#Exec & {
+			input: image.output
+			mounts: fs: {
+				dest:     "/scratch"
+				contents: scratch.output
+			}
+			workdir: "/"
+			args: [
+				"sh", "-c",
+				#"""
+					ls -al
+					"""#,
+			]
+		}
+
+	}
+}