add command test, fix relative paths

lib/src/compiler/compiler.dart

Index: lib/src/compiler/compiler.dart
diff --git a/lib/src/compiler/compiler.dart b/lib/src/compiler/compiler.dart
index 86009d52dfc97ea2403591f842d583e85ad726ea..41a05f72b3927b949dfcf08176856255bc536018 100644
--- a/lib/src/compiler/compiler.dart
+++ b/lib/src/compiler/compiler.dart
@@ -53,11 +53,11 @@ class ModuleCompiler {
     var errors = <AnalysisError>[];
 
     for (var sourcePath in unit.sources) {
-      String sourceUri = sourcePath;
-      if (path.isAbsolute(sourcePath)) {
-        sourceUri = path.toUri(sourcePath).toString();
+      var sourceUri = Uri.parse(sourcePath);
+      if (sourceUri.scheme == '') {
+        sourceUri = path.toUri(path.absolute(sourcePath));
       }
-      Source source = context.sourceFactory.forUri(sourceUri);
+      Source source = context.sourceFactory.forUri(sourceUri.toString());
       if (source == null) {
         throw new AnalysisException('could not create a source for $sourcePath.'
             ' The file name is in the wrong format or was not found.');