Add the ability to dynamically modify transforms to barback.

pkg/barback/test/package_graph/add_remove_transform_test.dart

Index: pkg/barback/test/package_graph/add_remove_transform_test.dart
diff --git a/pkg/barback/test/package_graph/add_remove_transform_test.dart b/pkg/barback/test/package_graph/add_remove_transform_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..b79c69afed00b1b9db7121436a4eaf60166595f2
--- /dev/null
+++ b/pkg/barback/test/package_graph/add_remove_transform_test.dart
@@ -0,0 +1,240 @@
+// 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 'package:barback/src/utils.dart';
+import 'package:scheduled_test/scheduled_test.dart';
+
+import '../utils.dart';
+
+main() {
+  initConfig();
+  test("a new transformer is applied to a matching asset", () {
+    initGraph(["app|foo.blub"]);
+
+    updateSources(["app|foo.blub"]);
+    expectAsset("app|foo.blub", "foo");
+    buildShouldSucceed();
+
+    updateTransformers("app", [[new RewriteTransformer("blub", "blab")]]);
+    expectAsset("app|foo.blab", "foo.blab");
+    expectNoAsset("app|foo.blub");
+    buildShouldSucceed();
+  });
+
+  test("a new transformer is not applied to a non-matching asset", () {
+    initGraph(["app|foo.blub"]);
+
+    updateSources(["app|foo.blub"]);
+    expectAsset("app|foo.blub", "foo");
+    buildShouldSucceed();
+
+    updateTransformers("app", [[new RewriteTransformer("zip", "zap")]]);
+    expectAsset("app|foo.blub", "foo");
+    expectNoAsset("app|foo.zap");
+    buildShouldSucceed();
+  });
+
+  test("updateTransformers doesn't re-run an old transformer", () {
+    var rewrite = new RewriteTransformer("blub", "blab");
+    initGraph(["app|foo.blub"], {"app": [[rewrite]]});
+
+    updateSources(["app|foo.blub"]);
+    expectAsset("app|foo.blab", "foo.blab");
+    expectNoAsset("app|foo.blub");
+    buildShouldSucceed();
+
+    updateTransformers("app", [[rewrite]]);
+    expectAsset("app|foo.blab", "foo.blab");
+    expectNoAsset("app|foo.blub");
+    buildShouldSucceed();
+
+    expect(rewrite.numRuns, completion(equals(1)));
+  });
+
+  test("updateTransformers re-runs old transformers in a new phase", () {
+    var rewrite1 = new RewriteTransformer("txt", "blub");
+    var rewrite2 = new RewriteTransformer("blub", "blab");
+    initGraph(["app|foo.txt"], {"app": [[rewrite1], [rewrite2]]});
+
+    updateSources(["app|foo.txt"]);
+    expectAsset("app|foo.blab", "foo.blub.blab");
+    expectNoAsset("app|foo.blub");
+    buildShouldSucceed();
+
+    updateTransformers("app", [[rewrite2], [rewrite1]]);
+    expectAsset("app|foo.blub", "foo.blub");
+    expectNoAsset("app|foo.blab");
+    buildShouldSucceed();
+  });
+
+  test("updateTransformers re-runs an old transformer when a previous phase "
+      "changes", () {
+    var rewrite = new RewriteTransformer("txt", "out");
+    initGraph(["app|foo.txt"], {"app": [[], [rewrite]]});
+
+    updateSources(["app|foo.txt"]);
+    expectAsset("app|foo.out", "foo.out");
+    buildShouldSucceed();
+
+    updateTransformers("app", [
+      [new RewriteTransformer("txt", "txt")],
+      [rewrite]
+    ]);
+    expectAsset("app|foo.out", "foo.txt.out");
+    buildShouldSucceed();
+  });
+
+  test("a removed transformer is no longer applied", () {
+    initGraph(["app|foo.blub"], {"app": [
+      [new RewriteTransformer("blub", "blab")]
+    ]});
+
+    updateSources(["app|foo.blub"]);
+    expectAsset("app|foo.blab", "foo.blab");
+    expectNoAsset("app|foo.blub");
+    buildShouldSucceed();
+
+    updateTransformers("app", []);
+    expectAsset("app|foo.blub", "foo");
+    expectNoAsset("app|foo.blab");
+    buildShouldSucceed();
+  });
+
+  test("a new transformer is pipelined", () {
+    var rewrite1 = new RewriteTransformer("source", "phase1");
+    var rewrite3 = new RewriteTransformer("phase2", "phase3");
+    initGraph(["app|foo.source"], {"app": [
+      [rewrite1],
+      [rewrite3]
+    ]});
+
+    updateSources(["app|foo.source"]);
+    expectNoAsset("app|foo.phase3");
+    buildShouldSucceed();
+
+    updateTransformers("app", [
+      [rewrite1],
+      [new RewriteTransformer("phase1", "phase2")],
+      [rewrite3]
+    ]);
+    expectAsset("app|foo.phase3", "foo.phase1.phase2.phase3");
+    buildShouldSucceed();
+  });
+
+  test("a removed transformer is un-pipelined", () {
+    var rewrite1 = new RewriteTransformer("source", "phase1");
+    var rewrite3 = new RewriteTransformer("phase2", "phase3");
+    initGraph(["app|foo.source"], {"app": [
+      [rewrite1],
+      [new RewriteTransformer("phase1", "phase2")],
+      [rewrite3]
+    ]});
+
+    updateSources(["app|foo.source"]);
+    expectAsset("app|foo.phase3", "foo.phase1.phase2.phase3");
+    buildShouldSucceed();
+
+    updateTransformers("app", [[rewrite1], [rewrite3]]);
+    expectNoAsset("app|foo.phase3");
+    buildShouldSucceed();
+  });
+
+  test("a transformer is removed during isPrimary", () {
+    var rewrite = new RewriteTransformer("blub", "blab");
+    initGraph(["app|foo.blub"], {"app": [[rewrite]]});
+
+    rewrite.pauseIsPrimary("app|foo.blub");
+    updateSources(["app|foo.blub"]);
+    // Ensure we're waiting on [rewrite.isPrimary].
+    schedule(pumpEventQueue);
+
+    updateTransformers("app", []);
+    rewrite.resumeIsPrimary("app|foo.blub");
+    expectAsset("app|foo.blub", "foo");
+    expectNoAsset("app|foo.blab");
+    buildShouldSucceed();
+  });
+
+  test("a transformer is removed during apply", () {
+    var rewrite = new RewriteTransformer("blub", "blab");
+    initGraph(["app|foo.blub"], {"app": [[rewrite]]});
+
+    rewrite.pauseApply();
+    updateSources(["app|foo.blub"]);
+    // Ensure we're waiting on [rewrite.apply].
+    schedule(pumpEventQueue);
+
+    updateTransformers("app", []);
+    rewrite.resumeApply();
+    expectAsset("app|foo.blub", "foo");
+    expectNoAsset("app|foo.blab");
+    buildShouldSucceed();
+  });
+
+  test("a new transformer can see pass-through assets", () {
+    var rewrite = new RewriteTransformer("zip", "zap");
+    initGraph(["app|foo.blub"], {"app": [[rewrite]]});
+
+    updateSources(["app|foo.blub"]);
+    buildShouldSucceed();
+
+    updateTransformers("app", [
+      [rewrite],
+      [new RewriteTransformer("blub", "blab")]
+    ]);
+    expectAsset("app|foo.blab", "foo.blab");
+    expectNoAsset("app|foo.blub");
+    buildShouldSucceed();
+  });
+
+  test("a cross-package transform sees a new transformer in a new phase", () {
+    // TODO(nweiz): make this work.
+    return;
+
+    var rewrite = new RewriteTransformer("inc", "inc");
+    initGraph({
+      "pkg1|foo.txt": "pkg2|foo.inc",
+      "pkg2|foo.inc": "foo"
+    }, {
+      "pkg1": [[new ManyToOneTransformer("txt")]],
+      "pkg2": [[rewrite]]
+    });
+
+    updateSources(["pkg1|foo.txt", "pkg2|foo.inc"]);
+    expectAsset("pkg1|foo.out", "foo");
+    buildShouldSucceed();
+
+    updateTransformers("pkg2", [
+      [rewrite],
+      [new RewriteTransformer("inc", "inc")]
+    ]);
+    expectAsset("pkg1|foo.out", "foo.inc.inc");
+    buildShouldSucceed();
+  });
+
+  test("a cross-package transform doesn't see a removed transformer in a "
+      "removed phase", () {
+    var rewrite = new RewriteTransformer("inc", "inc");
+    initGraph({
+      "pkg1|foo.txt": "pkg2|foo.inc",
+      "pkg2|foo.inc": "foo"
+    }, {
+      "pkg1": [[new ManyToOneTransformer("txt")]],
+      "pkg2": [
+        [rewrite],
+        [new RewriteTransformer("inc", "inc")]
+      ]
+    });
+
+    updateSources(["pkg1|foo.txt", "pkg2|foo.inc"]);
+    expectAsset("pkg1|foo.out", "foo.inc.inc");
+    buildShouldSucceed();
+
+    updateTransformers("pkg2", [[rewrite]]);
+    expectAsset("pkg1|foo.out", "foo.inc");
+    buildShouldSucceed();
+  });
+}