Model-based Testing
Introduction and Hands-on session
Stefan Ekman
Dublin, 2011-01-27
Model Based
Testing
What
is Model-based Testing?
What is MBT?
Wikipedia:
“Model-based testing is software testing in which test
cases are derived in whole or in part from a model that
describes some (usually functional) aspects of the system
under test (SUT).”
Advantages
• Model-based testing is easy to understand from both
the business and developer communities
• Model-based testing separates (business-) logic from
testing code
• Model-based testing increases the test coverage with
the same effort as “Classic” test automation
• Model-based testing is the fastest way to get use of
automated test
Advantages
• Model-based testing enables us to switch testing tool if
needed or support multiple platforms using the same
model
• Model-based testing focuses on requirement coverage,
not how many test cases you executed last week etc.
• Model-based testing proved to positively affect the
maintenance problem, the nemesis of all test
automation.
Modelling your tests
The Model
Tools / Environment
.GraphML
GraphWalker
Model with yEd
MBT engine
Hudson
Build system
Selenium
QTP
Java or SOAP
Via SOAP
Code behind
public void e_Nav_GoogleImages()
{
log.info("Edge: e_Nav_GoogleImages");
selenium.click(“link=Images");
selenium.waitForPageToLoad(30000);
}
Modelling
What should the model represent?
I suggest that you start with the model representing the
end usage/user functionality of the system. That will
usually resemble your traditional functional test case
approach. There are several other approaches for you
to explore later in you new MBT career…
Modelling
To what level do we model?
Modelling
Who creates the model?
• Start out yourself to begin with
• Present the model – show it to SME’s and
developers for input
• If the system is non-existing, you probably would
consider user stories, product backlog items, usecases or the equivalent requirement's information.
Modelling
During this process you will collect the first benefits of
working with MBT!
GraphWalker
GraphWalker is a tool for generating offline and online test sequences
from Finite State Machines and Extended Finite State Machines.
http://www.graphwalker.org/
•
•
•
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Lightweight MBT – No UML
No exit/stop points
Online
Event-driven
GraphWalker is an Open Source MBT engine created by Kristian Karl
and are stable and used in large IT testing environment.
GraphWalker - Stop Criteria's
•
•
•
•
•
•
•
•
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REACHED_EDGE
REACHED_VERTEX
EDGE_COVERAGE
VERTEX_COVERAGE
TEST_LENGTH
TEST_DURATION
REACHED_REQUIREMENT
REQUIEMENT_COVERAGE
NEVER
GraphWalker – XML configuration
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE MBTINIT SYSTEM "mbt_setup.dtd" >
<MBTINIT EXECUTOR="java:com.paddypower.mbt.BetPlacementRegression" EXTENDED="true"
GUI=“true">
<MODEL PATH="model/BetPlacementRegression.graphml"/>
<CLASS PATH="Java\PPautomation\bin"/>
<CLASS PATH=".\servlet-2.3.jar"/>
<CLASS PATH="selenium\selenium-java-client-driver.jar"/>
<CLASS PATH="selenium\selenium-server-2.0a6.jar"/>
<SCRIPT>
PortNumber = 5555;
DBconnectionString = "jdbc:informixsqli://10.10.10.10/db:informixserver=testdb1;user=user;password=12345";
MAX_SELECTIONS = 10;
</SCRIPT>
<GENERATOR TYPE="RANDOM">
<CONDITION TYPE="REACHED_VERTEX" VALUE="v_Done"/>
</GENERATOR>
</MBTINIT>
GraphWalker - The Walks
• RANDOM
• A_STAR
Will try to generate the shortest possible test
sequence through a model with given stop
condition. The algorithm only works well on
smaller models.
• SHORTEST_NON_OPTIMIZED
GraphWalker - Edge
• An edge is a transition. Could be a click on a button, a timeout, a
server API call.
• An edge can have a label, but it is not mandatory.
• The label of an edge will map against a method, function or sub
routine during test execution.
• As a rule of thumb, the best practice is to start the name with 'e_'.
The reason for this, is that it is easier to recognize the function in
the test execution tool, as an edge. For example:
e_StartApplication
e_EnterBasicView
• The same name of an edge, can be re-used in the model.
GraphWalker - Vertex
• A vertex is some kind of state that is possible to verify using some
kind of oracle.
• A vertex must always have a label.
• The label of a vertex is mapped against a method, function or sub
routine during test execution.
• As a rule of thumb, the best practice is to start the name with 'v_'.
The reason for this, is that it is easier to recognize the function in
the test execution tool, as a vertex. For example:
v_ApplicationStarted
v_BasicView
• The same name of a vertex, can be re-used in the model.
GraphWalker - Labels
Label [cond. expr.] / Statement1;Statement2;
White spaces not allowed.
Follow the naming convention for the implementing programming
language.
Example:
e_StartApplication
Example:
e_EnterBasicView
GraphWalker - Guards
Label [cond.expr.] / Statement1;Statement2;
Conditional expression that returns a Boolean value.
The guard indicates if the edge is accessible in the current state of the
machine. The language is either Java or JavaScript.
Example:
e_Evaluate [x>0 && y<=10]
Example:
e_Checkout [shoppingBasket.contains("Cerials")]
GraphWalker - Statements
Label [cond.expr.] / Statement1;Statement2;
Any applicable Java or JavaScript statements
Example:
e_Calculate / x=5;y++;
Example:
e_AddCerials / shoppingBasket.add("Cerials");
GraphWalker – Keyword Start
Used by Vertices only.
Each graph must have a start vertex, and that vertex holds this
keyword. There is only one vertex in a graph, holding this keyword.
The Start vertex can only have one out-edge.
If the graph is the main-graph, that edge must have a
label.
If the graph is a sub-graph, that edge cannot have a label.
GraphWalker - REQTAG
v_BookInfomation
REQTAG=UC01 2.2.3
Used by Vertices
Used by GraphWalker for keeping track of which
requirements are fulfilled during testing.
In the example above, if v_BookInfomation is passed, it
would mean the requirement with tag UC01 2.2.3 has
passed.
GraphWalker - Weight
v_BookInfomation
REQTAG=UC01 2.2.3
e_NavA
weight=0.25
e_NavB
Used by Edges only.
Used by MBT during random walks during test sequence
generation. It holds a real value between 0 and 1, and
represents the probability that a specific edge should be
chosen. A value of 0.05, would mean a 5% chance of
that edge to be selected during a run.
Note: It only works with the RANDOM generator
GraphWalker – Keyword Blocked
Used by both Vertices and Edges.
A vertex or an edge with the key word BLOCKED, will be
excluded from the model when walked.
v_BookInfomation
BLOCKED
Metrics
• Standard test metrics does not apply so well.
• Test cases are not meaningful when running online
tests.
• MBT tends to drive the requirement work.
GraphWalker – QTP & SOAP
WebService("SoapServicesService").SetTOProperty "WSDL",
"http://myComputerName:9090/mbt-services?WSDL"
If ( not WebService("SoapServicesService").Reload() )Then
Reporter.ReportEvent micFail, "MBT failure", "MBT encountered an
error. See the MBT log files for information."
ExitTest
End If
Do until not WebService("SoapServicesService").HasNextStep()
action = WebService("SoapServicesService").GetNextStep()
If len(action) > 0 Then
If not Eval( action ) Then
Reporter.ReportEvent micFail, "Script failure", "The
script encountered an error when trying to run function: " & action
ExitTest
End if
End If
Loop
Reporter.ReportEvent micDone, "MBT Statistics",
WebService("SoapServicesService").GetStatistics()
5 min break..
I am not in the office at the moment. Please send any
work to be translated.
Hands on session
1.
2.
3.
4.
5.
6.
Setup the environment
Create a model
Generate code from model
Automate with selenium
Create XML configuration file for GraphWalker
Run the model!
Files
1. Create directory MBT i.e C:\MBT
2. Create directory Models under in the MBT folder
3. Copy GraphWalker and Selenium jar files to the
directory
selenium-java-client-driver.jar
selenium-server.jar
graphwalker-2.5.1-SNAPSHOT-standalone.jar
Model
Visit www.brickor.com/MBT.htm with Firefox
Record with Selenium IDE by clicking on all elements and
as well right clicking the result
Switch off recording.
Options > Format > JUnit4 (Java)
Model
Start yEd to create the model
Generate the Java Code
/**
* This method implements the {EDGE_VERTEX} '{LABEL}'
*/
public void {LABEL}()
{
log.info( "{EDGE_VERTEX}: {LABEL}" );
throw new RuntimeException( "The {EDGE_VERTEX}: {LABEL} is
not implemented yet!" );
}
java -jar graphwalker-2.5.1-SNAPSHOT-standalone.jar
source -f Models/mbttest.graphml -t
java.template.txt > javacode.txt
Eclipse – Create the Java project
Create new Java Project; MbtTest
Create new Java Package; ie.mbt.test
Create new Class; MBTtest
Copy paste the contents of the generated Java code from
the model into the created class.
The java code
Include references to Selenium and GraphWalker in your project. Right click on your project
and choose Properties. Under Java Build Path choose Libraries and then click Add
External JARs.. Choose the two jar files:
graphwalker-2.5.1-SNAPSHOT-standalone.jar
selenium-java-client-driver.jar
private HttpCommandProcessor proc = new
HttpCommandProcessor("localhost",4444, "*chrome",
“http://www.brickor.com/MBT.htm”);
private Selenium selenium = new DefaultSelenium(proc);
private Logger log = Util.setupLogger(MBTtest.class);
// import org.apache.log4j.Logger;
// import org.graphwalker.Util;
Writing the Java Code
In e_init we start the selenium object.
selenium.start();
selenium.open("http://www.brickor.com/MBT.htm");
Delete the Throw exception!
Update all e_r11, e_r12 etc
selenium.click("Radio1_1");
row1 = Integer.parseInt(selenium.getText(“r11"));
Writing the Java Code
Create the utility GetResult
public boolean GetResult()
{
int rowTotal = row1 + row2 + row3;
int calcTotal =
Integer.parseInt(selenium.getText("totalDiv"));
if (rowTotal==calcTotal)
return true;
else
return false;
}
IMPORTANT!
Compile you class after any changes, CTRL + B
GraphWalker XML
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE MBTINIT SYSTEM "mbt_setup.dtd" >
<MBTINIT EXECUTOR="java:ie.mbt.test.MBTtest" EXTENDED="true">
<MODEL PATH="models/MBTTest.graphml"/>
<CLASS PATH="MbtTest\bin"/>
<CLASS PATH="selenium-java-client-driver.jar"/>
<CLASS PATH="selenium-server.jar"/>
<GENERATOR TYPE="RANDOM">
<CONDITION TYPE="TEST_LENGTH" VALUE="1000"/>
</GENERATOR>
</MBTINIT>
Selenium Server
java -jar selenium-server.jar
Will start with default settings on port 4444
Start the scripts..
Command line to start GraphWalker with the correct
settings:
java -jar graphwalker-2.5.1-SNAPSHOT-standalone.jar gui
xml -f MBTTest.xml
Questions?
More info at:
www.graphwalker.org
mbt.tigris.org
http://en.wikipedia.org/wiki/Model-based_testing
Email: stefan.ekman@gmail.com