DbUnit Framework

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DbUnit Framework

• Joe BoroskyChris DeCellesYvonne Krashkevich

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DbUnit Framework

• Database Testing with DbUnit
• In this presentation, we are going to explain how
  to get started with DbUnit.
• The Environment
• Sample Eclipse project which contains DbUnit and
  JUnit.

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DbUnit Framework

• DbUnit extends the popular JUnit test framework.
• JUnit
• JUnit is a regression testing framework written
  by Erich Gamma and Kent Beck.
• It is used by those who implement unit tests in
  Java.
• It is open source software.
• It is an instance of the xUnit architecture for
  unit testing frameworks.

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DbUnit Framework

• JUnit Features
• Assertions for testing expected results
• Text fixtures for sharing common test data
• Test suites for easily organizing and running
  tests
• Graphical and textual test runners

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DbUnit Framework

• Unit Test Frameworks
• Unit Test Frameworks are a key element in eXtreme
  Programming and Agile Development.
• Unit Testing has moved beyond eXtreme Programming
• It is common in many types of application
  development.
• They help ensure low level code correctness,
  reduce software development cycle time, improve
  developer productivity, and produce more robust
  software.

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DbUnit Best Practices

• DBUnit Best Practices
• Use one database instance per developer
• If you setup the tests properly you do not have
  to cleanup afterwards.
• Use multiple small datasets instead of using one
  large dataset (most tests do not require the
  entire database to re-initialize).
• Perform setup of stale data once for the entire
  test class or test suite
• Connection Management Strategies
• Remote Client with Database Test Case
• In-container with Cactus or JUnitEE

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DbUnit Framework

• Database Testing with DbUnit
• DbUnit is a useful and powerful tool for
  simplifying unit testing of database operations.
• It is targeted for Database-driven projects and
  works to put your database into a known state
  between test runs.
• With DbUnit, a database can be seeded with a
  desired data set before a test moreover, at the
  completion of the test, the database can be
  placed back into its pre-test state.

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DbUnit Framework

• Database Testing with DbUnit
• It is a great tool to use to avoid the problems
  that may occur when one test case corrupts the
  database and causes subsequent test to fail.
• It can work with very large datasets when used in
  streaming mode.
• It can help verify your data matches an expected
  set of values.

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DbUnit Framework

• DbUnit Features for Unit Testing Database
  Operations
• a very simple XML-based mechanism for loading
  test data
• a framework which simplifies operations for each
  stage in the life cycle of individual database
  tests
• an equally simple mechanism for exporting
  existing test data into the XML format for
  subsequent use in automated tests
• methods for comparing data, between flat files,
  queries and database tables

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DbUnit Framework

• DbUnit Core Components
• IDatabaseConnection - interface representing a
  DbUnit connection to a DB
• IDataSet - interface representing a collection of
  tables
• DatabaseOperation - abstract class representing
  an operation performed on the database before and
  after each test

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DbUnit Framework

• DbUnit IDatabaseConnection
• DatabaseConnection - wraps a JDBC connection
• DatabaseDataSourceConnection - wraps a JDBC Data
  Source

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DbUnit Framework

• DbUnit IDataSet
• This is the primary abstraction used by DbUnit to
  manipulate tabular data.
• Commonly used implementations
• FlatXmlDataSet DefaultDataSet
• XmlDataSet CompositeDataSet
• StreamingDataSet FilteredDataSet
• DatabaseDataSet XlsDataSet
• QueryDataSet ReplacementDataSet

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DbUnit Framework

• DbUnit DatabaseOperation
• Operations (named DatabaseOperation.xyz)
• UPDATE TRUNCATE
• INSERT REFRESH
• DELETE CLEAN_INSERT
• DELETE_ALL NONE
• Other Operations
• CompositeOperation
• TransactionOperation
• IdentityInsertOperation

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DbUnit Framework

• Create a DbUnit Test Case
• The easiest way to understand how DbUnit is used
  is through an example.
• The first thing to know is
• Instead of subclassing JUnit's TestCase class
  directly
• Subclass DbUnit's DatabaseTestCase, which is
  itself a subclass of TestCase.
• DatabaseTestCase is abstract, and requires you to
  implement two methods
• protected IDatabaseConnection getConnection()
  throws Exception
• protected IDataSet getDataSet() throws Exception.

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DbUnit Framework

• Create a DbUnit Test Case
• IDatabaseConnection getConnection() throws
  Exception.
• The first thing that needed is to specify how to
  obtain a database connection.
• protected IDatabaseConnection getConnection()
  throws Exception
• Class driverClass Class.forName("com.mysql.jdbc
  .Driver")
• Connection jdbcConnection DriverManager.getCon
  nection("jdbcmysql//localhost3306/Framework
• Database", "root", password")
• return new DatabaseConnection(jdbcConnection)

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DbUnit Framework

• Create a DbUnit Test Case
• IDataSet getDataSet() throws Exception.
• Here the method returns a data set loaded from an
  XML file on the classpath.
• protected IDataSet getDataSet() throws Exception
• loadedDataSet new FlatXmlDataSet(
  this.getClass().getClassLoader().getResourceAsStre
  am("input.xml")) return loadedDataSet

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DbUnit Framework

• Create a DbUnit Test Case
• DbUnit has adopted a very flexible architecture
  based on intelligent use of interfaces. IDataSet
  is one of the key interfaces. The best way to
  think of IDataSet is that it represents one or
  more blocks of tabular data.
• This data may be generated from a number of
  sources
• flat XML files, of which we will see an example
  very shortly
• tables in the database
• database queries created using SQL
• less obvious sources, such as Microsoft Excel
  spreadsheets

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DbUnit Framework

• Create a DbUnit Test Case
• The IDataSet interface is very powerful
• First because it defines a common representation
  which can be used for comparisons between data
  from any of these sources
• Second because it defines methods for reading
  from and writing to its native format.

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DbUnit Framework

• Create a DbUnit Test Case
• Probably the most widely used mechanism for
  creating a test data set is the flat XML file
  format.
• lt?xml version'1.0' encoding'UTF-8'?gt
• ltdatasetgt
• ltMANUFACTURER FIELD_1"1" FIELD_2"IBM"
  FIELD_3"Laptop" FIELD_4"2005-10-08"
  FILED_5"000000"/gt
• ltMANUFACTURER FIELD_1"2" FIELD_2"DELL"
  FIELD_3"Desktop" FIELD_4"2005-10-09"
  FILED_5"000000"/gt
• lt/datasetgt

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DbUnit Framework

• Create a DbUnit Test Case
• The test case contains data from a single table,
  MANUFACTURER, with five data columns.
• Our getDataSet() implementation uses the
  FlatXmlDataSet class to load this file.
• The test class is not ready, because we haven't
  written any tests yet. Before we can do this, we
  need to understand the DbUnit test life cycle. In
  particular, we want to know what it does with the
  IDataSet it has loaded in the getDataSet() method.

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DbUnit Framework

• The DbUnit Test LifeCycle
• The most typical scenario for running database
  tests using DbUnit is as follows
• remove any old stale data left in the database
  from previous tests
• load some data from the file system into the
  database
• run some tests, using DbUnit methods to make
  assertions

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DbUnit Framework

• The DbUnit Test LifeCycle
• Both of the first two operations occur during
  execution of the JUnit setUp() method. Note that
  with this scenario, no attempt is made to restore
  database state after running tests. This is the
  recommended best practice by the authors of
  DbUnit.

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DbUnit Framework

• The DbUnit Test LifeCycle
• Cleanup occurs before the test is run, not after.
  This approach is more productive when
  circumstances allow it, because you do not need
  to waste time writing code to restore state,
  which can be quite a significant task in some
  situations.
• The tests may run a little slower, but the idea
  is that setup should only load data required for
  an individual test, rather than data required for
  all tests.

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DbUnit Framework

• The DbUnit Test LifeCycle
• Lets take a look at how the setUp() and
  tearDown() methods are implemented in the
  DatabaseTestCase class.

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DbUnit Framework

• protected void setUp() throws Exception
• super.setUp()
• executeOperation(getSetUpOperation())
• protected void tearDown() throws Exception
• super.tearDown()
• executeOperation(getTearDownOperation())

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DbUnit Framework

• /
• Returns the database operation executed in
  test setup.
• /
• protected DatabaseOperation getSetUpOperation()
  throws Exception
• return DatabaseOperation.CLEAN_INSERT
• /
• Returns the database operation executed in
  test cleanup.
• /
• protected DatabaseOperation getTearDownOperation()
  throws Exception
• return DatabaseOperation.NONE

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DbUnit Framework

• The DbUnit Test LifeCycle
• The setUp() method executes the setup operation,
  DatabaseOperation.CLEAN_INSERT.
• This operation in fact combines two operations
  DELETE_ALL and INSERT.
• DELETE_ALL removes all data from the database for
  the tables returned using getDataSet(), then
  inserts the data loaded using that method.
• This is how the data that we define in our flat
  XML file is loaded into the database.

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DbUnit Framework

• The DbUnit Test LifeCycle
• The operation NONE executed in tearDown(), does
  nothing.
• The default setUp() and tearDown() operations can
  be overridden if your application requires this.
• You can even provide your own implementation of
  IDatabaseOperation.

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DbUnit Framework

• Writing Tests
• Now that we understand the DbUnit lifecycle and
  we've set up the necessary infrastructure, we're
  ready to write some tests. The following tests
  demonstrate some features of DbUnit, rather than
  testing a specific application.
• First Test Example - Demonstrates that the
  setUp() method does indeed load the XML data into
  an IDataSet instance, and that this data contains
  the data we expect.

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DbUnit Framework

• private FlatXmlDataSet loadedDataSet
• protected IDataSet getDataSet() throws Exception
• loadedDataSet new FlatXmlDataSet(this.getC
  lass().getClassLoader().getResourceAsStream("input
  .xml"))
• return loadedDataSet
• public void testCheckDataLoaded() throws
  Exception
• assertNotNull(loadedDataSet)
• int rowCount loadedDataSet.getTable(TABL
  E_NAME).getRowCount()
• assertEquals(2, rowCount)

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DbUnit Framework

• Writing Tests
• Second Test Example - Shows how we can create an
  IDataSet using the IDatabaseConnection for a
  particular table.
• The IDatabaseConnection is created using the
  IDatabaseConnection getConnection().
• Notice that this is only using one table,
  although the IDataSet could contain data for
  multiple tables.

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DbUnit Framework

• public void testCompareDataSet() throws Exception
  
• IDataSet createdDataSet getConnection().createD
  ataSet(new String
• TABLE_NAME
• )
• Assertion.assertEquals(loadedDataSet,
  createdDataSet)

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DbUnit Framework

• Writing Tests
• We mentioned earlier that DbUnit included a
  mechanism for comparing data loaded from
  different sources. You can see this at work in
  this test example the Assertion.assertEquals()
  method compares data obtained from the database
  with the data loaded from the XML file.

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DbUnit Framework

• Writing Tests
• Third Test Example - Takes this idea further. It
  shows how we can create an IDataSet instance
  using SQL queries, and use this as a basis for
  assertions

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DbUnit Framework

• public void testCompareQuery() throws Exception
• QueryDataSet queryDataSet new
  queryDataSet(getConnection()) queryDataSet.addTab
  le(TABLE_NAME, "SELECT FROM " TABLE_NAME)
  Assertion.assertEquals(loadedDataSet,
  queryDataSet)

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DbUnit Framework

• This is very powerful because it means you can
  create data sets which represent arbitrary
  queries, and not simply tables in the database.
• Many of the DbUnit test that will be written in
  real application are likely to use this mechanism.

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DbUnit Framework

• Writing Tests
• Final Test Example - Shows how to export a data
  set, either from an existing database table or
  from a query, into a flat XML file.
• The FlatXmlDataSet.write() method is used to
  write the data set to the file output.xml in the
  DbUnit XML format.

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DbUnit Framework

• public void testExportData() throws Exception
• IDataSet dataSet getConnection().createDataSet(
  new String
• TABLE_NAME
• )
• URL url DatabaseTestCase.class.getResource("/in
  put.xml") assertNotNull(url)
• File inputFile new File(url.getPath())
• File outputFile new File(inputFile.getParent(),
  "output.xml") FlatXmlDataSet.write(dataSet, new
  FileOutputStream(outputFile))
• assertEquals(FileUtils.readFileToString(inputFile
  , "UTF8"), FileUtils.readFileToString(outputFile,
  "UTF8"))

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DbUnit Framework

• Writing Tests
• Our test also asserts that the contents of the
  outputted XML file are identical to the input.xml
  from which the IDataSet was originally loaded.

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DbUnit Framework

• Summary
• DbUnit is a powerful, simple to use tool for
  enabling test driven development of database
  applications.
• It is well designed around flexible Java
  interfaces, which make it easy to adapt or extend
  to application requirements.
• It is simple to include DbUnit as a part of your
  database application development process and take
  advantage of its powerful, timesaving features.

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DbUnit Framework

• Summary
• The DbUnit framework's ability to manage the
  state of a database throughout a test's lifecycle
  enables rapid test-case creation and adoption
  furthermore, by controlling a major dependency,
  tests that utilize the DbUnit framework are
  easily automated.
• DbUnit's elegant design makes learning how to
  properly utilize its features a breeze. Once it's
  in place as a part of an effective testing
  strategy, overall code stability will increase
  dramatically, along with the collective
  confidence of your development team.

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DbUnit Framework

• QUESTIONS?

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DbUnit Framework

• Sources
• http//www.realsolve.co.uk/site/tech/dbunit-quicks
  tart.php
• http//www.onjava.com/pub/a/onjava/2004/01/21/dbun
  it.html
• http//dbunit.sourceforge.net/
• http//www.dbunit.org/apidocs/index.html
• http//www.eclipse.org/
• http//perl.about.com/od/installandconfiguremysql/
  l/aa112400b.htm
• http//dev.mysql.com/doc/mysql/en/create-database.
  html