Don't pass an asset through a transformer that produces an error.

pkg/barback/test/package_graph/errors_test.dart

Index: pkg/barback/test/package_graph/errors_test.dart
diff --git a/pkg/barback/test/package_graph/errors_test.dart b/pkg/barback/test/package_graph/errors_test.dart
index 2728859aa2849987793c4e06fd1ed5907d5bb4f6..d1bb5c25546c50a4b2c1469ab4fb36ac0725c4a9 100644
--- a/pkg/barback/test/package_graph/errors_test.dart
+++ b/pkg/barback/test/package_graph/errors_test.dart
@@ -173,164 +173,11 @@ main() {
     ]);
   });
 
-  test("a collision returns the first-produced output", () {
-    var rewrite1 = new RewriteTransformer("one", "out");
-    var rewrite2 = new RewriteTransformer("two", "out");
-    initGraph({
-      "app|foo.one": "one",
-      "app|foo.two": "two"
-    }, {"app": [[rewrite1, rewrite2]]});
-
-    rewrite1.pauseApply();
-    updateSources(["app|foo.one", "app|foo.two"]);
-    // Wait long enough to ensure that rewrite2 has completed.
-    schedule(pumpEventQueue);
-
-    rewrite1.resumeApply();
-    expectAsset("app|foo.out", "two.out");
-    buildShouldFail([isAssetCollisionException("app|foo.out")]);
-
-    // Even after the collision is discovered, the first-produced output should
-    // be returned.
-    expectAsset("app|foo.out", "two.out");
-
-    // Even if the other output is updated more recently, the first output
-    // should continue to take precedence.
-    updateSources(["app|foo.one"]);
-    expectAsset("app|foo.out", "two.out");
-  });
-
-  test("a collision that is later resolved produces an output", () {
-    initGraph({
-      "app|foo.one": "one",
-      "app|foo.two": "two"
-    }, {"app": [
-      [
-        new RewriteTransformer("one", "out"),
-        new RewriteTransformer("two", "out")
-      ]
-    ]});
-
-    updateSources(["app|foo.one"]);
-    expectAsset("app|foo.out", "one.out");
-    buildShouldSucceed();
-
-    updateSources(["app|foo.two"]);
-    expectAsset("app|foo.out", "one.out");
-    buildShouldFail([isAssetCollisionException("app|foo.out")]);
-
-    removeSources(["app|foo.one"]);
-    expectAsset("app|foo.out", "two.out");
-    buildShouldSucceed();
-  });
-
-  test("a collision that is later resolved runs transforms", () {
-    initGraph({
-      "app|foo.one": "one",
-      "app|foo.two": "two"
-    }, {"app": [
-      [
-        new RewriteTransformer("one", "mid"),
-        new RewriteTransformer("two", "mid")
-      ],
-      [new RewriteTransformer("mid", "out")]
-    ]});
-
-    updateSources(["app|foo.one"]);
-    expectAsset("app|foo.out", "one.mid.out");
-    buildShouldSucceed();
-
-    updateSources(["app|foo.two"]);
-    expectAsset("app|foo.out", "one.mid.out");
-    buildShouldFail([isAssetCollisionException("app|foo.mid")]);
-
-    removeSources(["app|foo.one"]);
-    expectAsset("app|foo.out", "two.mid.out");
-    buildShouldSucceed();
-  });
-
-  test("a collision that is partially resolved returns the second completed "
-      "output", () {
-    var rewrite1 = new RewriteTransformer("one", "out");
-    var rewrite2 = new RewriteTransformer("two", "out");
-    var rewrite3 = new RewriteTransformer("three", "out");
-    initGraph({
-      "app|foo.one": "one",
-      "app|foo.two": "two",
-      "app|foo.three": "three"
-    }, {"app": [[rewrite1, rewrite2, rewrite3]]});
-
-    // Make rewrite3 the most-recently-completed transformer from the first run.
-    rewrite2.pauseApply();
-    rewrite3.pauseApply();
-    updateSources(["app|foo.one", "app|foo.two", "app|foo.three"]);
-    schedule(pumpEventQueue);
-    rewrite2.resumeApply();
-    schedule(pumpEventQueue);
-    rewrite3.resumeApply();
-    buildShouldFail([
-      isAssetCollisionException("app|foo.out"),
-      isAssetCollisionException("app|foo.out")
-    ]);
-
-    // Then update rewrite3 in a separate build. rewrite2 should still be the
-    // next version of foo.out in line.
-    // TODO(nweiz): Should this emit a collision error as well? Or should they
-    // only be emitted when a file is added or removed?
-    updateSources(["app|foo.three"]);
-    buildShouldSucceed();
-
-    removeSources(["app|foo.one"]);
-    expectAsset("app|foo.out", "two.out");
-    buildShouldFail([isAssetCollisionException("app|foo.out")]);
-  });
-
-  test("a collision with a pass-through asset returns the pass-through asset",
-      () {
-    initGraph([
-      "app|foo.txt",
-      "app|foo.in"
-    ], {"app": [
-      [new RewriteTransformer("in", "txt")]
-    ]});
-
-    updateSources(["app|foo.txt", "app|foo.in"]);
-    expectAsset("app|foo.txt", "foo");
-    buildShouldFail([isAssetCollisionException("app|foo.txt")]);
-  });
-
-  test("a new pass-through asset that collides returns the previous asset", () {
-    initGraph([
-      "app|foo.txt",
-      "app|foo.in"
-    ], {"app": [
-      [new RewriteTransformer("in", "txt")]
-    ]});
-
-    updateSources(["app|foo.in"]);
-    expectAsset("app|foo.txt", "foo.txt");
-    buildShouldSucceed();
-
-    updateSources(["app|foo.txt"]);
-    expectAsset("app|foo.txt", "foo.txt");
-    buildShouldFail([isAssetCollisionException("app|foo.txt")]);
-  });
-
-  test("a new transform output that collides with a pass-through asset returns "
-      "the pass-through asset", () {
-    initGraph([
-      "app|foo.txt",
-      "app|foo.in"
-    ], {"app": [
-      [new RewriteTransformer("in", "txt")]
-    ]});
+  test("an asset isn't passed through a transformer with an error", () {
+    initGraph(["app|foo.txt",], {"app": [[new BadTransformer([])]]});
 
     updateSources(["app|foo.txt"]);
-    expectAsset("app|foo.txt", "foo");
-    buildShouldSucceed();
-
-    updateSources(["app|foo.in"]);
-    expectAsset("app|foo.txt", "foo");
-    buildShouldFail([isAssetCollisionException("app|foo.txt")]);
+    expectNoAsset("app|foo.txt");
+    buildShouldFail([isTransformerException(equals(BadTransformer.ERROR))]);
   });
 }