TDD with DbFit and OracleWriting readable, easy to maintain unit and integration tests for

database code

Yavor Nikolov

BGOUG Conference, 2013-05-18

Agenda

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Concepts (Testing, Test-Driven Development)

DbFit

Demo

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What is a legacy system?

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You spot an obvious design problem

know how to improve that,

but the thought about consequences gives you astomach ache.

source: Gojko Adzic, "Fighting the monster"

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#bgoug2013

source: http://lisacrispin.com/2011/11/08/using-the-agile-testing-quadrants

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Why (automated) testing?

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Makes application change easier

Safety net - provides confidence/removes fear

Documentation

Help to localize where exactly a defect is located

Reduce the chance of new bugs

Automation enables earlier feedback, saves time,helps focusing on solving the main problem. (Noteverything is feasible to automate)

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Test Fixture

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All the things we need to have in place in order torun a test and expect a particular outcome

The test context

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System Under Test (SUT)

The system that is being tested

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Test execution cycle

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Arrange (set up the Fixture)

Act (exercise the System Under Test)

Assert (verify results are as expected)

Tear Down the fixture (to isolate other tests fromthis one)

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Unit test

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Tests small individual unit (module,procedure/function)

In isolation (no interaction with other units)

Should run quickly (otherwise people won't runthem)

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Integration test

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Tests several modules as a group

Slower than unit tests (usually)

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Acceptance test

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Conducted to determine whether or not a systemsatisfies its acceptance criteria

and to enable the customer to determine whether ornot to accept the system.

At least modeled and possibly even written by thecustomer

End-to-end (slower than Integration & Unit tests)

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Regression tests(Regress vs progress)

Performed to make sure that previously workingfunctionality still works after changes elsewhere inthe system

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Refactor

Is the the process of changing a system in such a waythat

Doing refactoring without tests is unsafe

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doesn't alter external behaviour

and improves it's internal structure (design)

through small steps

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TDD Cycle

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source: Internet

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Tests are not the main product in TDD

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TDD is a design technique

The design emerges in small steps

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Why test first?

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Start with end in mind (think from point of view ofcaller)

This perspective helps for better design

Test coverage is useful byproduct

Greatly reduces the need of debugging

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Cost of change (traditional)

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Cost of change (test early)

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Why testing the Database?

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For lot of businesses, data held in DB are the mostvital commercial asset they have

Business critical functions rely on this data

So it makes sense to validate that data is stored andprocessed correctly

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Challenges of Database testing...

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Bad tools

Inherently hard to test. Isolation is difficult

Attitude ("it's not my job")

Too much boilerplate code

OO tools not directly applicable for RDBMS

Changes are persistent

Shared environment

Triggers, Constraints

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How to isolate db tests?Run tests in one transaction

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Makes them repeatable and independent

When one transaction is not an option - clean upafter tests

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How to isolate db tests (2)?Dedicated database

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One db per contributor

Separate schemas

Shared Dev db may work too

As a rule - avoid running tests on top of production

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Other Tips

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Make tests self-sufficient

Don't count on the order of tests

Prepare everything you need for the test in its set-up

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#bgoug2013

DbFit

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What is DbFit?

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Initially created by Gojko Adzic:

Enables manipulating database objects and definingtests in tabular form

Open source https://github.com/benilovj/dbfit

to enable efficient database testing

motivate database developers to use anautomated testing framework

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DbFit, FIT and FitNesse

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DbFit is based on FIT+FitNesse+DB Fixtures whichenable FIT/Fitnesse tests to execute directly against adatabase.

FIT is Acceptance testing framework

FitNesse is Wiki-web based front-end for FIT

customer oriented

tests are described as tables

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FitNesse architecture

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source: Fittnesse User Guilde - One Minute Description

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What is DbFit Fixture?

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A fixture is interface between:

In general there is 1:1 mapping between Fit tableand fixture

the test instrumentation (Fit framework),

test cases (Fit tables),

and the system under test (e.g. a databasestored procedure)

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Why DbFit?

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Easy to use (even for non-technical people)

Provides all the plumbing:

Runs inside FitNesse - already integrated with lots ofother tools/libraries

Tests expressed and managed as tables

Web-Wiki front-end

Transaction management

Features based on meta-data

Parameter mapping

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What is Wiki?

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The simplest online database that could possiblywork. - Ward Cunningham

Allows users to freely create and edit Web pagecontent using any Web browser

A group communication mechanisms

Encourages democratic use of the Web andpromotes content composition by nontechnicalusers

source: http://wiki.org/wiki.cgi?WhatIsWiki

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Fitnesse Wiki

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Hierarchies - SubWiki, Test Suites

Page types - Suite, Test, Static

Some special pages:

http://fitnesse.org/FitNesse.UserGuide

PageHeader, PageFooter

SetUp, TearDown, SuiteSetUp, SuiteTearDown

Inherited recurively by default; can be overriden

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A Unit test with DbFit

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Set up the input data (arrange).

Execute a function or procedure (act).

Run a query and compare actual vs expected data(assert).

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2.

3.

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Basic commands of DbFit

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Query

Insert

Update

Execute Procedure

Execute

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Advanced features

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Inspect queries, tables, procedures to auto-generatetest tables and regression tests

Store and compare queries

Standalone mode for full control

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Getting started

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Needs Java to run

Download: http://benilovj.github.io/dbfit

Unzip

Copy Oracle JDBC driver (ojdbc6.jar) to lib subfolder

Run the startup script (startFitnesse.sh orstartFitnesse.bat)

Access via web browser - http://localhost:8085

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Connecting to the database

Inline configuration:

Using properties file:

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!|Connect|localhost:1521|username|password|dbname|

!|ConnectUsingFile|DBConnection.properties|

service=localhost:1521username=usernamepassword=passworddatabase=dbname

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Query

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!|insert|testtbl||n |name ||1 |NAME1 ||3 |NAME3 ||2 |NAME2 |

!|query|select * from testtbl||n |name ||1 |NAME1 ||3 |NAME3 ||2 |NAME2 |

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Ordered Query

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!|Ordered Query|select * from testtbl order by n||n |name? ||1 |NAME1 ||3 |NAME3 ||2 |NAME2 |

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Insert

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!|insert|testtbl||n |name ||1 |NAME1 ||3 |NAME3 ||2 |NAME2 |

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Execute Procedure

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!2 No parameters!|Execute Procedure|do_stuff|

!2 Functions - return values with "?"!|Execute Procedure|zlpad_notrunc ||p_str |p_padded_len|? ||'12' |5 |'00012' |

!2 OUT parameters - "?" suffix!|Execute Procedure|split_name||p_fullname |p_first_name?|p_last_name?||Mikey Mouse|Mickey |Mouse |

!2 IN OUT parameters - specify twice!|Execute Procedure|make_double||x|x?||3|6 |

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Expect exception

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!2 Expect ORA-20013!|Execute procedure expect exception|set_age|20013||p_age ||-5 |

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Parameters and fixture symbols

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set parameter to set parameter directly

>>paramname - store a value

<<paramname - read the value

!|set parameter|ONE|1|

!|query|select sysdate mytime from dual||mytime? ||>>current_time |

!|query|select count(*) cnt from dual where sysdate >= :current_time||cnt ||<<ONE |

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Store Query

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!|Store Query|select 1 n from dual union select 2 n from dual|firsttable|

!|query|<<firsttable||n ||1 ||2 |

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Compare Stored Queries

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!|insert|testtbl||n |name ||1 |NAME1 ||3 |NAME3 ||2 |NAME2 |

|Store Query|select * from testtbl|fromtable|

|Store Query|!- select 1 n, 'name1' name from dual|fromdual|

|compare stored queries|fromtable|fromdual||name |n? |

Use ? suffix for non-key columns

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Working Modes of fixtures

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Flow

Standalone

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Working Modes of fixtures (2)Flow mode

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A DatabaseTest fixture controls the whole page andcoordinates testing

Automatic rollback at the end (manual commit orrollback is still possible)

Better isolation

Some additional features such as inspections ofstored procedure error results

OracleTest, MysqlTest, DerbyTest, DB2Test, ...

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Working Modes of fixtures (3)Standalone mode

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We are responsible for transaction management

Enables more control over the database testingprocess

Allows using other individual fixtures

We can supply our own database connection tomake sure that (Java) integration tests are running inthe same transaction

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Connecting to databse

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!3 In Flow mode!|dbfit.OracleTest|!|Connect|ourhost:1521|dbusername|dbpassword|mydb|

# Alternatively - TNS descriptor can be used:#!|Connect|(DESCRIPTION=(ADDRESS=...))|

!3 In Standalone mode|import fixture||dbfit.fixture|!|DatabaseEnvironment|oracle||connect|localhost:1521|dbusername|dbpassword|mydb|

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Integration test with SQL*Loader

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Compile CommandLineFixture (by Bob Martin)

Use it to run a shell script

!3 Load some data with Oracle SQL*Loader|com.objectmentor.fixtures.CommandLineFixture ||command|${PROJECT_ROOT}/loaderdemo/load_employee.sh|

!|Query|select * from employee ||id |name? |dept? |salary?||100 |Thomas|Sales |5000 ||200 |Jason |Technology|5500 ||300 |Mayla |Technology|7000 ||400 |Nisha |Marketing |9500 ||500 |Randy |Technology|6000 ||501 |Ritu |Accounting|5400 |

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Automating tests execution

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Running tests from command line

Run test or suite as RESTful servicehttp://fitnesse.org/FitNesse.UserGuide.RestfulServices

JUnit

java -jar fitnesse-standalone.jar \ -d "${TESTS_DIR}" \ -c "BgougDemoSuite?suite&format=text"

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How tests are stored?

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Simple text files

content.txt - test definition and other Wiki content

properties.xml - metadata (Test, Sute)

Easy to put under version control

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#bgoug2013

Demo

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Summary

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Changes of database code and schema are oftenrelatively hard

This makes the systems considered legacy

TDD stimulates designing cleaner and easier tochange code

Development of RDBMS artefacts is lagging when itcomes to engineering practices and tools

DbFit can help

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Resources

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http://benilovj.github.io/dbfit - with links to:

https://github.com/javornikolov/tdd-with-dbfit-bgoug-201305

http://gojko.net/2007/11/20/fighting-the-monster

http://www.agiledata.org/essays/tdd.html, http://www.agiledata.org

Test Driven Development: By Example, Kent Beck

Refactoring Databases - Evolutionary Database Design, Scott W. Ambler, Pramodkumar J. Sadalage

download DbFit

docs, getting started information

mailing list - don't hesitate to participate and ask questions

code repository at github - reports for problems, suggestions and contributions are welcome

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Thank You!nikolov dot javor at gmail

Q&A

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