Github user afs commented on a diff in the pull request:
https://github.com/apache/jena/pull/314#discussion_r154233681
--- Diff:
jena-arq/src/test/java/org/apache/jena/sparql/core/assembler/TestDatasetAssembler.java
---
@@ -0,0 +1,122 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.jena.sparql.core.assembler;
+
+import static java.nio.file.Files.createTempFile;
+import static org.apache.jena.assembler.JA.data;
+import static org.apache.jena.assembler.Mode.DEFAULT;
+import static org.apache.jena.rdf.model.ModelFactory.createDefaultModel;
+import static org.apache.jena.riot.Lang.NQUADS;
+import static org.apache.jena.riot.RDFDataMgr.write;
+import static org.apache.jena.vocabulary.RDF.type;
+
+import java.io.*;
+import java.nio.file.Path;
+
+import org.apache.jena.assembler.JA;
+import org.apache.jena.assembler.exceptions.CannotConstructException;
+import org.apache.jena.query.Dataset;
+import org.apache.jena.rdf.model.*;
+import org.apache.jena.sparql.core.*;
+import org.apache.jena.sparql.sse.SSE;
+import org.apache.jena.sparql.util.IsoMatcher;
+import org.apache.jena.system.Txn;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestDatasetAssembler extends Assert {
--- End diff --
I was lookign for tests that do both `ja:data` and `ja:defaultGraph`, which
should be an error. I saw someone asking recently trying with `ja:defaultGraph`
and TIM assemble, which just ignores unknown properties. Easy confusion to
make - so deliberately testing making an error seems sensible.
---
