Only run [declareOutputs] once for each asset/transformer pair.

pkg/barback/test/package_graph/declaring_transformer_test.dart

+// Copyright (c) 2014, 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.declaring_transformer_test;
+
+import 'package:barback/barback.dart';
+import 'package:barback/src/utils.dart';
+import 'package:scheduled_test/scheduled_test.dart';
+
+import '../utils.dart';
+
+main() {
+  initConfig();
+
+  test("gets a declared output with a different path", () {
+    initGraph(["app|foo.blub"], {"app": [
+      [new DeclaringRewriteTransformer("blub", "blab")]
+    ]});
+    updateSources(["app|foo.blub"]);
+    expectAsset("app|foo.blab", "foo.blab");
+    buildShouldSucceed();
+  });
+
+  test("gets a declared output with the same path", () {
+    initGraph(["app|foo.blub"], {"app": [
+      [new DeclaringRewriteTransformer("blub", "blub")]
+    ]});
+    updateSources(["app|foo.blub"]);
+    expectAsset("app|foo.blub", "foo.blub");
+    buildShouldSucceed();
+  });
+
+  test("gets a passed-through asset", () {
+    initGraph(["app|foo.blub"], {"app": [
+      [new DeclaringRewriteTransformer("blub", "blab")]
+    ]});
+    updateSources(["app|foo.blub"]);
+    expectAsset("app|foo.blub", "foo");
+    buildShouldSucceed();
+  });
+
+  test("doesn't get a consumed asset", () {
+    initGraph(["app|foo.blub"], {"app": [
+      [new DeclaringRewriteTransformer("blub", "blab")..consumePrimary = true]
+    ]});
+    updateSources(["app|foo.blub"]);
+    expectNoAsset("app|foo.blub");
+    buildShouldSucceed();
+  });
+
+  test("gets a passed-through asset before apply is finished", () {

[Bob Nystrom, 2014/04/08 18:23:44]

What if it doesn't declare that it will overwrite the asset, but then does?

[nweiz, 2014/04/08 23:42:33]

I think we should assume that it won't, but start returning the overwritten
asset if it does. I'll add a test for this.

+    var transformer = new DeclaringRewriteTransformer("blub", "blab");
+    initGraph(["app|foo.blub"], {"app": [[transformer]]});
+
+    transformer.pauseApply();
+    updateSources(["app|foo.blub"]);
+    expectAsset("app|foo.blub", "foo");
+
+    transformer.resumeApply();
+    buildShouldSucceed();
+  });
+
+  test("fails to get a consumed asset before apply is finished", () {
+    var transformer = new DeclaringRewriteTransformer("blub", "blab")
+        ..consumePrimary = true;
+    initGraph(["app|foo.blub"], {"app": [[transformer]]});
+
+    transformer.pauseApply();
+    updateSources(["app|foo.blub"]);
+    expectNoAsset("app|foo.blub");
+
+    transformer.resumeApply();
+    buildShouldSucceed();
+  });
+
+  test("waits to get an overwritten asset until apply is finished", () {

[Bob Nystrom, 2014/04/08 18:23:44]

The grammar is weird here. How about "waits until apply is finished to...".

[nweiz, 2014/04/08 23:42:33]

Done.

+    var transformer = new DeclaringRewriteTransformer("blub", "blub");
+    initGraph(["app|foo.blub"], {"app": [[transformer]]});
+
+    transformer.pauseApply();
+    updateSources(["app|foo.blub"]);
+    expectAssetDoesNotComplete("app|foo.blub");
+
+    transformer.resumeApply();
+    expectAsset("app|foo.blub", "foo.blub");
+    buildShouldSucceed();
+  });
+
+  group("with an error in declareOutputs", () {
+    test("still runs apply", () {
+      initGraph(["app|foo.txt"], {"app": [[
+        new DeclaringBadTransformer("app|out.txt",
+            declareError: true, applyError: false)
+      ]]});
+
+      updateSources(["app|foo.txt"]);
+      expectAsset("app|out.txt", "bad out");
+      expectAsset("app|foo.txt", "foo");
+      buildShouldFail([isTransformerException(BadTransformer.ERROR)]);
+    });
+
+    test("waits for apply to complete before passing through the input even if "
+        "consumePrimary was called", () {
+      var transformer = new DeclaringBadTransformer("app|out.txt",
+            declareError: true, applyError: false)..consumePrimary = true;
+      initGraph(["app|foo.txt"], {"app": [[transformer]]});
+
+      transformer.pauseApply();
+      updateSources(["app|foo.txt"]);
+      expectAssetDoesNotComplete("app|out.txt");
+      expectAssetDoesNotComplete("app|foo.txt");
+
+      transformer.resumeApply();
+      expectAsset("app|out.txt", "bad out");
+      expectNoAsset("app|foo.txt");
+      buildShouldFail([isTransformerException(BadTransformer.ERROR)]);
+    });
+  });
+
+  test("with an error in apply still passes through the input", () {
+   initGraph(["app|foo.txt"], {"app": [[
+     new DeclaringBadTransformer("app|out.txt",
+         declareError: false, applyError: true)
+   ]]});
+
+   updateSources(["app|foo.txt"]);
+   expectNoAsset("app|out.txt");
+   expectAsset("app|foo.txt", "foo");
+   buildShouldFail([isTransformerException(BadTransformer.ERROR)]);
+  });
+
+  test("can emit outputs it didn't declare", () {

[Bob Nystrom, 2014/04/08 18:23:44]

What about overwriting the primary if it didn't declare it would?

[nweiz, 2014/04/08 23:42:33]

See above.

+    initGraph(["app|foo.txt"], {"app": [
+      [new DeclareAssetsTransformer([], ["app|out.txt"])]
+    ]});
+
+    updateSources(["app|foo.txt"]);
+    // There's probably going to be some time when "out.txt" is unavailable,
+    // since it was undeclared.
+    schedule(pumpEventQueue);

[Bob Nystrom, 2014/04/08 18:23:44]

This is super sketchy.

[nweiz, 2014/04/08 23:42:33]

In what way?

[Bob Nystrom, 2014/04/09 18:07:08]

The comment says "probably" and then just waits an arbitrary amount of time. Is
this behavior actually deterministic?

[nweiz, 2014/04/09 20:11:52]

It's not arbitrary; it waits until there are no additional events in the event
queue (or as close as possible without doing zone stuff); in this case, until
the transformer is finished running. It's the same way we use [pumpEventQueue]
everywhere else.

+    expectAsset("app|out.txt", "app|out.txt");
+    buildShouldSucceed();
+  });
+
+  test("can declare outputs it doesn't emit", () {

[Bob Nystrom, 2014/04/08 18:23:44]

This should at least be a warning.

[nweiz, 2014/04/08 23:42:33]

Done.

+    initGraph(["app|foo.txt"], {"app": [
+      [new DeclareAssetsTransformer(["app|out.txt"], [])]
+    ]});
+
+    updateSources(["app|foo.txt"]);
+    expectNoAsset("app|out.txt");
+    buildShouldSucceed();
+  });
+}