--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api.test/src/com/oracle/truffle/api/test/source/SourceTagTest.java	Sun May 31 17:19:04 2015 -0700
@@ -0,0 +1,162 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.truffle.api.test.source;
+
+import static org.junit.Assert.*;
+
+import org.junit.*;
+
+import com.oracle.truffle.api.source.*;
+
+public class SourceTagTest {
+
+    @Test
+    public void sourceTagTest() {
+
+        // Private tag
+        final SourceTag testTag = new SourceTag() {
+
+            public String name() {
+                return null;
+            }
+
+            public String getDescription() {
+                return null;
+            }
+        };
+
+        // No sources exist with the private tag
+        assertEquals(Source.findSourcesTaggedAs(testTag).size(), 0);
+
+        // Create a new source
+        final Source source = Source.fromText("test1 source", "test1 source");
+
+        // Initially has only the default tag
+        assertEquals(source.getSourceTags().size(), 1);
+
+        assertTrue(source.getSourceTags().contains(Source.Tags.FROM_LITERAL));
+        assertTrue(source.isTaggedAs(Source.Tags.FROM_LITERAL));
+        assertTrue(Source.findSourcesTaggedAs(Source.Tags.FROM_LITERAL).contains(source));
+
+        assertFalse(source.isTaggedAs(testTag));
+        assertEquals(Source.findSourcesTaggedAs(testTag).size(), 0);
+
+        // Add a private tag
+        source.tagAs(testTag);
+
+        // Now there are exactly two tags
+        assertEquals(source.getSourceTags().size(), 2);
+
+        assertTrue(source.getSourceTags().contains(Source.Tags.FROM_LITERAL));
+        assertTrue(source.isTaggedAs(Source.Tags.FROM_LITERAL));
+        assertTrue(Source.findSourcesTaggedAs(Source.Tags.FROM_LITERAL).contains(source));
+
+        assertTrue(source.getSourceTags().contains(testTag));
+        assertTrue(source.isTaggedAs(testTag));
+        assertEquals(Source.findSourcesTaggedAs(testTag).size(), 1);
+        assertTrue(Source.findSourcesTaggedAs(testTag).contains(source));
+
+        // Add the private tag again
+        source.tagAs(testTag);
+
+        // Nothing has changed
+        assertEquals(source.getSourceTags().size(), 2);
+
+        assertTrue(source.getSourceTags().contains(Source.Tags.FROM_LITERAL));
+        assertTrue(source.isTaggedAs(Source.Tags.FROM_LITERAL));
+        assertTrue(Source.findSourcesTaggedAs(Source.Tags.FROM_LITERAL).contains(source));
+
+        assertTrue(source.getSourceTags().contains(testTag));
+        assertTrue(source.isTaggedAs(testTag));
+        assertEquals(Source.findSourcesTaggedAs(testTag).size(), 1);
+        assertTrue(Source.findSourcesTaggedAs(testTag).contains(source));
+    }
+
+    @Test
+    public void sourceListenerTest() {
+
+        // Private tag
+        final SourceTag testTag = new SourceTag() {
+
+            public String name() {
+                return null;
+            }
+
+            public String getDescription() {
+                return null;
+            }
+        };
+
+        final int[] newSourceEvents = {0};
+        final Source[] newSource = {null};
+
+        final int[] newTagEvents = {0};
+        final Source[] taggedSource = {null};
+        final SourceTag[] newTag = {null};
+
+        Source.addSourceListener(new SourceListener() {
+
+            public void sourceCreated(Source source) {
+                newSourceEvents[0] = newSourceEvents[0] + 1;
+                newSource[0] = source;
+            }
+
+            public void sourceTaggedAs(Source source, SourceTag tag) {
+                newTagEvents[0] = newTagEvents[0] + 1;
+                taggedSource[0] = source;
+                newTag[0] = tag;
+            }
+        });
+
+        // New source has a default tag applied.
+        // Get one event for the new source, another one when it gets tagged
+        final Source source = Source.fromText("testSource", "testSource");
+        assertEquals(newSourceEvents[0], 1);
+        assertEquals(newSource[0], source);
+        assertEquals(newTagEvents[0], 1);
+        assertEquals(taggedSource[0], source);
+        assertEquals(newTag[0], Source.Tags.FROM_LITERAL);
+
+        // reset
+        newSource[0] = null;
+        taggedSource[0] = null;
+        newTag[0] = null;
+
+        // Add a tag; only get one event (the new tag)
+        source.tagAs(testTag);
+        assertEquals(newSourceEvents[0], 1);
+        assertEquals(newSource[0], null);
+        assertEquals(newTagEvents[0], 2);
+        assertEquals(taggedSource[0], source);
+        assertEquals(newTag[0], testTag);
+
+        // Add the same tag; no events, and nothing changes.
+        source.tagAs(testTag);
+        assertEquals(newSourceEvents[0], 1);
+        assertEquals(newSource[0], null);
+        assertEquals(newTagEvents[0], 2);
+        assertEquals(taggedSource[0], source);
+        assertEquals(newTag[0], testTag);
+
+    }
+}