First pass at build dependency graph for barback.

pkg/barback/test/asset_graph/errors_test.dart

Index: pkg/barback/test/asset_graph/errors_test.dart
diff --git a/pkg/barback/test/asset_graph/errors_test.dart b/pkg/barback/test/asset_graph/errors_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..45a36de2abca3e48fe3c5fdded9d97df23da69d7
--- /dev/null
+++ b/pkg/barback/test/asset_graph/errors_test.dart
@@ -0,0 +1,220 @@
+// 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.asset_graph.source_test;
+
+import 'dart:async';
+
+import 'package:barback/barback.dart';
+import 'package:barback/src/asset_graph.dart';
+import 'package:scheduled_test/scheduled_test.dart';
+
+import '../utils.dart';
+
+main() {
+  initConfig();
+
+  test("errors if two transformers output the same file", () {
+    var provider = new MockProvider(["app|foo.a"]);
+    var graph = new AssetGraph(provider, [
+      [
+        new RewriteTransformer("a", "b"),
+        new RewriteTransformer("a", "b")
+      ]
+    ]);
+    graph.updateSources([new AssetId.parse("app|foo.a")]);
+
+    expectCollision(graph, "app|foo.b");
+  });
+
+  test("reports asset not found errors in results", () {
+    var provider = new MockProvider([]);
+    var graph = new AssetGraph(provider, []);
+
+    // TODO(rnystrom): This is verbose and ugly. Better would be to have
+    // utils.dart register this on the graph and then have functions to expect
+    // certain build results.
+    var numResults = 0;
+    var gotError = false;
+    graph.results.listen(wrapAsync((result) {
+      numResults++;
+      expect(numResults, lessThan(3));
+
+      if (numResults == 1) {
+        // Should complete the build first.
+        expect(result.error, isNull);
+      } else if (numResults == 2) {
+        // Then have the error.
+        expect(result.error, new isInstanceOf<AssetNotFoundException>());
+        expect(result.error.id, equals(new AssetId.parse("app|foo.txt")));
+        gotError = true;
+      }
+    }));
+
+    expectNoAsset(graph, "app|foo.txt");
+
+    schedule(() {
+      expect(gotError, isTrue);
+    });
+  });
+
+  test("reports an error for an unprovided source", () {
+    var provider = new MockProvider([]);
+    var graph = new AssetGraph(provider, []);
+    var resultFuture = graph.results.first;
+
+    graph.updateSources([new AssetId.parse("app|unknown.txt")]);
+
+    schedule(() {
+      return resultFuture.then((result) {
+        expect(result.error, new isInstanceOf<AssetNotFoundException>());
+        expect(result.error.id, equals(new AssetId.parse("app|unknown.txt")));
+      });
+    });
+  });
+
+  test("reports missing input errors in results", () {
+    var provider = new MockProvider({"app|a.txt": "a.inc"});
+
+    var graph = new AssetGraph(provider, [
+      [new ManyToOneTransformer("txt")]
+    ]);
+
+    var gotError = false;
+    graph.results.listen(wrapAsync((result) {
+      expect(result.error is MissingInputException, isTrue);
+      expect(result.error.id, equals(new AssetId.parse("app|a.inc")));
+      gotError = true;
+    }));
+
+    graph.updateSources([new AssetId.parse("app|a.txt")]);
+
+    expectNoAsset(graph, "app|a.out");
+
+    schedule(() {
+      expect(gotError, isTrue);
+    });
+  });
+
+  test("fails if a non-primary input is removed", () {
+    var provider = new MockProvider({
+      "app|a.txt": "a.inc,b.inc,c.inc",
+      "app|a.inc": "a",
+      "app|b.inc": "b",
+      "app|c.inc": "c"
+    });
+
+    var graph = new AssetGraph(provider, [
+      [new ManyToOneTransformer("txt")]
+    ]);
+
+    // TODO(rnystrom): This is verbose and ugly. Better would be to have
+    // utils.dart register this on the graph and then have functions to expect
+    // certain build results.
+    var numResults = 0;
+    var gotError = false;
+    graph.results.listen(wrapAsync((result) {
+      numResults++;
+      expect(numResults, lessThan(3));
+
+      if (numResults == 1) {
+        // Should complete the build first.
+        expect(result.error, isNull);
+      } else if (numResults == 2) {
+        // Then have the error.
+        expect(result.error is MissingInputException, isTrue);
+        expect(result.error.id, equals(new AssetId.parse("app|b.inc")));
+        gotError = true;
+      }
+    }));
+
+    graph.updateSources([
+      new AssetId.parse("app|a.txt"),
+      new AssetId.parse("app|a.inc"),
+      new AssetId.parse("app|b.inc"),
+      new AssetId.parse("app|c.inc")
+    ]);
+
+    expectAsset(graph, "app|a.out", "abc");
+
+    schedule(() {
+      graph.removeSources([new AssetId.parse("app|b.inc")]);
+    });
+
+    expectNoAsset(graph, "app|a.out");
+
+    schedule(() {
+      expect(gotError, isTrue);
+    });
+  });
+
+  test("catches transformer exceptions and reports them", () {
+    var provider = new MockProvider(["app|foo.txt"]);
+    var graph = new AssetGraph(provider, [
+      [new BadTransformer(["app|foo.out"])]
+    ]);
+
+    var gotError = false;
+    graph.results.listen(wrapAsync((result) {
+      expect(result.error, equals(BadTransformer.ERROR));
+      gotError = true;
+    }));
+
+    schedule(() {
+      graph.updateSources([new AssetId.parse("app|foo.txt")]);
+    });
+
+    expectNoAsset(graph, "app|foo.out");
+
+    schedule(() {
+      expect(gotError, isTrue);
+    });
+  });
+
+  // TODO(rnystrom): Is this the behavior we expect? If a transformer fails
+  // to transform a file, should we just skip past it to the source?
+  test("yields a source if a transform fails on it", () {
+    var provider = new MockProvider(["app|foo.txt"]);
+    var graph = new AssetGraph(provider, [
+      [new BadTransformer(["app|foo.txt"])]
+    ]);
+
+    schedule(() {
+      graph.updateSources([new AssetId.parse("app|foo.txt")]);
+    });
+
+    expectAsset(graph, "app|foo.txt");
+  });
+
+  test("catches errors even if nothing is waiting for process results", () {
+    var provider = new MockProvider(["app|foo.txt"]);
+    var graph = new AssetGraph(provider, [[new BadTransformer([])]]);
+    var resultFuture = graph.results.first;
+
+    schedule(() {
+      graph.updateSources([new AssetId.parse("app|foo.txt")]);
+    });
+
+    // Note: No asset requests here.
+
+    schedule(() {
+      return resultFuture.then((result) {
+        expect(result.error, equals(BadTransformer.ERROR));
+      });
+    });
+  });
+
+  test("discards outputs from failed transforms", () {
+    var provider = new MockProvider(["app|foo.txt"]);
+    var graph = new AssetGraph(provider, [
+      [new BadTransformer(["a.out", "b.out"])]
+    ]);
+
+    schedule(() {
+      graph.updateSources([new AssetId.parse("app|foo.txt")]);
+    });
+
+    expectNoAsset(graph, "app|a.out");
+  });
+}