The basic pattern of unit testing with Neo4j is illustrated by the following example.
To access the Neo4j testing facilities you should have the neo4j-kernel tests.jar on the classpath during tests.
You can download it from Maven Central: org.neo4j:neo4j-kernel.
Using Maven as a dependency manager you would typically add this dependency together with JUnit and Hamcrest like so:
Maven dependency.
<project> ... <dependencies> <dependency> <groupId>org.neo4j</groupId> <artifactId>neo4j-kernel</artifactId> <version>1.9.1</version> <type>test-jar</type> <scope>test</scope> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit-dep</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <dependency> <groupId>org.hamcrest</groupId> <artifactId>hamcrest-all</artifactId> <version>1.3</version> <scope>test</scope> </dependency> ... </dependencies> ... </project>
Observe that the <type>test-jar</type> is crucial.
Without it you would get the common neo4j-kernel jar, not the one containing the testing facilities.
With that in place, we’re ready to code our tests.
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For the full source code of this example see: Neo4jBasicDocTest.java |
Before each test, create a fresh database:
@Before
public void prepareTestDatabase()
{
graphDb = new TestGraphDatabaseFactory().newImpermanentDatabase();
}
After the test has executed, the database should be shut down:
@After
public void destroyTestDatabase()
{
graphDb.shutdown();
}
During a test, create nodes and check to see that they are there, while enclosing write operations in a transaction.
Transaction tx = graphDb.beginTx();
Node n = null;
try
{
n = graphDb.createNode();
n.setProperty( "name", "Nancy" );
tx.success();
}
catch ( Exception e )
{
tx.failure();
}
finally
{
tx.finish();
}
// The node should have an id greater than 0, which is the id of the
// reference node.
assertThat( n.getId(), is( greaterThan( 0L ) ) );
// Retrieve a node by using the id of the created node. The id's and
// property should match.
Node foundNode = graphDb.getNodeById( n.getId() );
assertThat( foundNode.getId(), is( n.getId() ) );
assertThat( (String) foundNode.getProperty( "name" ), is( "Nancy" ) );
If you want to set configuration parameters at database creation, it’s done like this:
Map<String, String> config = new HashMap<String, String>();
config.put( "neostore.nodestore.db.mapped_memory", "10M" );
config.put( "string_block_size", "60" );
config.put( "array_block_size", "300" );
GraphDatabaseService db = new TestGraphDatabaseFactory()
.newImpermanentDatabaseBuilder()
.setConfig( config )
.newGraphDatabase();
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