Support passing barback assets through phases in which they're unused.

pkg/barback/test/package_graph/transform_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library barback.test.package_graph.transform_test;
 
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 import 'package:barback/src/utils.dart';
@@ skipping 585 matching lines @@
     schedule(pumpEventQueue);
 
     removeSources(["app|foo.txt"]);
     rewrite.resumeIsPrimary("app|foo.txt");
     expectNoAsset("app|foo.txt");
     buildShouldSucceed();
   });
 
   test("doesn't transform an asset that goes from primary to non-primary "
       "during isPrimary", () {
-    var check = new CheckContentTransformer("do", "ne");
+    var check = new CheckContentTransformer(new RegExp(r"^do$"), "ne");
     initGraph({
       "app|foo.txt": "do"
     }, {"app": [[check]]});
 
     check.pauseIsPrimary("app|foo.txt");
     updateSources(["app|foo.txt"]);
     // Make sure we're waiting on isPrimary.
     schedule(pumpEventQueue);
 
     modifyAsset("app|foo.txt", "don't");
@@ skipping 38 matching lines @@
     removeSources(["app|foo.txt"]);
     rewrite2.resumeIsPrimary("app|foo.md");
     expectNoAsset("app|foo.txt");
     expectAsset("app|foo.md", "foo.md");
     buildShouldSucceed();
   });
 
   test("doesn't transform an asset that goes from primary to non-primary "
       "during another transformer's isPrimary", () {
     var rewrite = new RewriteTransformer("md", "md");
-    var check = new CheckContentTransformer("do", "ne");
+    var check = new CheckContentTransformer(new RegExp(r"^do$"), "ne");
     initGraph({
       "app|foo.txt": "do",
       "app|foo.md": "foo"
     }, {"app": [[rewrite, check]]});
 
     rewrite.pauseIsPrimary("app|foo.md");
     updateSources(["app|foo.txt", "app|foo.md"]);
     // Make sure we're waiting on the correct isPrimary.
     schedule(pumpEventQueue);
 
@@ skipping 126 matching lines @@
     updateSources(["pkg2|foo.txt"]);
     expectAsset("pkg1|foo.out", "foo.out");
     buildShouldNotBeDone();
 
     // Now that the provider is unpaused, pkg2's transforms finish and the
     // overall build succeeds.
     resumeProvider();
     buildShouldSucceed();
   });
 
+  group("pass-through", () {
+    test("passes an asset through a phase in which no transforms apply", () {
+      initGraph([
+        "app|foo.in",
+        "app|bar.zip",
+      ], {"app": [
+        [new RewriteTransformer("in", "mid")],
+        [new RewriteTransformer("zip", "zap")],
+        [new RewriteTransformer("mid", "out")],
+      ]});
+
+      updateSources(["app|foo.in", "app|bar.zip"]);
+      expectAsset("app|foo.out", "foo.mid.out");
+      expectAsset("app|bar.zap", "bar.zap");
+      buildShouldSucceed();
+    });
+
+    test("doesn't pass an asset through a phase in which a transform consumes "
+        "it", () {
+      initGraph([
+        "app|foo.in",
+      ], {"app": [
+        [new RewriteTransformer("in", "mid")],
+        [new RewriteTransformer("mid", "phase2")],
+        [new RewriteTransformer("mid", "phase3")],
+      ]});
+
+      updateSources(["app|foo.in"]);
+      expectAsset("app|foo.phase2", "foo.mid.phase2");
+      expectNoAsset("app|foo.phase3");
+      buildShouldSucceed();
+    });
+
+    test("removes a pass-through asset when the source is removed", () {
+      initGraph([
+        "app|foo.in",
+        "app|bar.zip",
+      ], {"app": [
+        [new RewriteTransformer("zip", "zap")],
+        [new RewriteTransformer("in", "out")],
+      ]});
+
+      updateSources(["app|foo.in", "app|bar.zip"]);
+      expectAsset("app|foo.out", "foo.out");
+      buildShouldSucceed();
+
+      removeSources(["app|foo.in"]);
+      expectNoAsset("app|foo.in");
+      expectNoAsset("app|foo.out");
+      buildShouldSucceed();
+    });
+
+    test("updates a pass-through asset when the source is updated", () {
+      initGraph([
+        "app|foo.in",
+        "app|bar.zip",
+      ], {"app": [
+        [new RewriteTransformer("zip", "zap")],
+        [new RewriteTransformer("in", "out")],
+      ]});
+
+      updateSources(["app|foo.in", "app|bar.zip"]);
+      expectAsset("app|foo.out", "foo.out");
+      buildShouldSucceed();
+
+      modifyAsset("app|foo.in", "boo");
+      updateSources(["app|foo.in"]);
+      expectAsset("app|foo.out", "boo.out");
+      buildShouldSucceed();
+    });
+
+    test("passes an asset through a phase in which transforms have ceased to "
+        "apply", () {
+      initGraph([
+        "app|foo.in",
+      ], {"app": [
+        [new RewriteTransformer("in", "mid")],
+        [new CheckContentTransformer("foo.mid", ".phase2")],
+        [new CheckContentTransformer(new RegExp(r"\.mid$"), ".phase3")],
+      ]});
+
+      updateSources(["app|foo.in"]);
+      expectAsset("app|foo.mid", "foo.mid.phase2");
+      buildShouldSucceed();
+
+      modifyAsset("app|foo.in", "bar");
+      updateSources(["app|foo.in"]);
+      expectAsset("app|foo.mid", "bar.mid.phase3");
+      buildShouldSucceed();
+    });
+
+    test("doesn't pass an asset through a phase in which transforms have "
+        "started to apply", () {
+      initGraph([
+        "app|foo.in",
+      ], {"app": [
+        [new RewriteTransformer("in", "mid")],
+        [new CheckContentTransformer("bar.mid", ".phase2")],
+        [new CheckContentTransformer(new RegExp(r"\.mid$"), ".phase3")],
+      ]});
+
+      updateSources(["app|foo.in"]);
+      expectAsset("app|foo.mid", "foo.mid.phase3");
+      buildShouldSucceed();
+
+      modifyAsset("app|foo.in", "bar");
+      updateSources(["app|foo.in"]);
+      expectAsset("app|foo.mid", "bar.mid.phase2");
+      buildShouldSucceed();
+    });
+  });
+
   group('cross-package transforms', () {
     test("can access other packages' source assets", () {
       initGraph({
         "pkg1|a.txt": "pkg2|a.inc",
         "pkg2|a.inc": "a"
       }, {"pkg1": [[new ManyToOneTransformer("txt")]]});
 
       updateSources(["pkg1|a.txt", "pkg2|a.inc"]);
       expectAsset("pkg1|a.out", "a");
       buildShouldSucceed();
@@ skipping 99 matching lines @@
       buildShouldSucceed();
 
       modifyAsset("pkg2|a.inc", "b");
       updateSources(["pkg2|a.inc"]);
       expectAsset("pkg1|b", "spread out");
       expectNoAsset("pkg1|c.done");
       buildShouldSucceed();
     });
   });
 }