fix #620, infer the input files from sources

tool/build_test_pkgs.sh

Index: tool/build_test_pkgs.sh
diff --git a/tool/build_test_pkgs.sh b/tool/build_test_pkgs.sh
new file mode 100755
index 0000000000000000000000000000000000000000..1e45949945739844a04e44fe13eb8e3ab1013e0d
--- /dev/null
+++ b/tool/build_test_pkgs.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+set -e # bail on error
+
+cd $( dirname "${BASH_SOURCE[0]}" )/..
+
+mkdir -p gen/codegen_output/pkg/
+
+SDK=--dart-sdk-summary=lib/runtime/dart_sdk.sum
+
+./bin/dartdevc.dart $SDK -o gen/codegen_output/pkg/expect.js \
+    --url-mapping=package:expect/expect.dart,test/codegen/expect.dart \
+    package:expect/expect.dart
+
+./bin/dartdevc.dart $SDK  -o gen/codegen_output/pkg/async_helper.js \
+    --url-mapping=package:async_helper/async_helper.dart,test/codegen/async_helper.dart \
+    package:async_helper/async_helper.dart
+
+./bin/dartdevc.dart $SDK  -o gen/codegen_output/pkg/js.js \
+    package:js/js.dart
+
+./bin/dartdevc.dart $SDK  -o gen/codegen_output/pkg/matcher.js \
+    package:matcher/matcher.dart
+
+./bin/dartdevc.dart $SDK  -o gen/codegen_output/pkg/stack_trace.js \
+    package:stack_trace/stack_trace.dart
+
+./bin/dartdevc.dart $SDK  -o gen/codegen_output/pkg/path.js \
+    package:path/path.dart
+
+./bin/dartdevc.dart $SDK  -o gen/codegen_output/pkg/unittest.js \
+    package:unittest/unittest.dart \
+    package:unittest/html_config.dart \
+    package:unittest/html_individual_config.dart \
+    package:unittest/html_enhanced_config.dart