Stub :
Stubs are dummy modules which are known as "called programs" which is used in integration testing (top down approach), used when sub programs are under construction. A stub may simulate the behavior of existing code (such as a procedure on a remote machine) or be a temporary substitute for yet-to-be-developed code.
Example 1:
| BEGIN
Temperature = ThermometerRead(Outside)
IF Temperature > 40 THEN
PRINT "It's HOT!"
END IF
END
|
| BEGIN ThermometerRead(Source insideOrOutside)
RETURN 28
END ThermometerRead
|
Example 2: A drive program to calculate_income_taxfunction may consist line like
Cout << “income tax on 50000 is:”;
Cout << calculate_income_tax(5000)<<“\n”;
Example 3:
void function_under_test(int& x, int& y) {
...
p = price(x);
...
}
double price(int x) {return 10.00;}
The value returned by function price is good enough for testing. The real price() function may not yet have been tested, or even written.
Driver:
Drivers are kind of dummy modules which are known as "calling programs", which is used in bottom up integration testing, used when main programs are under construction.
Example 1: to move a fighter on the game, the driver code would be
moveFighter(Fighter, LocationX, LocationY);
This driver code would likely be called from the main method. A white-box test case would execute this driver line of code and check fighter.getPosition() to make sure the player is now on the expected cell on the board.
This driver code would likely be called from the main method. A white-box test case would execute this driver line of code and check fighter.getPosition() to make sure the player is now on the expected cell on the board.
Example 2: Edouble calculate_salary (double hours, double rate)
{ cout<< “salary is : ”;
return (hours*rate);
}
The main program can be tested using this code
Example 3:
#include <iostream.h>
void get_input(x& cost, int& y);
int main( )
{
double a;
int b;
char ans;
do
{
get_input(a, b);
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);
cout << "a is " << a << endl;
cout << "b is " << b << endl;
cout << "Test again?"
<< " (Type y for yes or n for no): ";
cin >> ans;
cout << endl;
} while (ans == 'y' || ans == 'Y');
return 0;
}
Difference between stub and driver:
Stub
|
Driver
|
A piece of code that simulates the activity of missing component
|
A piece of code that passes test case to another piece of code
|
Stubs are created integration testing like Top-down approach
|
Drivers are created integration testing like bottom-up approach
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Stubs are simulations of the sub-code that otherwise is very gives full control to the test code
|
Driver takes care that the entry point of the application is masked by that of the test code and difficult to execute in the test code
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A stub is a brief section of compliable code that serves as a class
|
A driver is a brief test program that demonstrates the functionality of a class or a portion of placeholder for future work
|
It is a temporary called program. It functions similarly like sub modules
|
It is a temporary Calling program. It functions similarly like main module for calling the sub when called by the main module
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Stub is a simple routine that takes the place of the real routine Stubs let you check the interfaces and higher levels of the program
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The driver approach is to write a program that passes input data to the unit under test and compares the output to the truth
|
Stub is a piece of special code that which is used to simulate the set up environment missing or not yet constructed
|
Driver is a code that which invokes the code to be tested
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Stub is a skeleton of function having function header. This function can have actual statements or simple statements which can be replaced with the actual code
|
Driver is a small program used to test a function
|
A driver creates necessary ‘Inputs’ required for the Unit and then invokes the Unit
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A driver creates necessary ‘Inputs’ required for the Unit and then invokes the Unit
|
Stub
|
Driver
|
Stubs can be "filled in" to form the actual method
|
Drivers can become automated test cases
|
Example: In module A and module B, module A ready and module B is not. For integration testing of module A, a dummy module is created which stimulate like module B. This dummy module is Stub.
|
Example: module B cannot send or receive data from module A automatically so, in such case we have to transfer data from one module to another module by some external features. This external feature used is called Driver.
|
References:
- Pressman, Roger S., Software Engineering: A Practitioner's Approach (P 459-462), New Delhi, 2011
- http://www.qualitytesting.info/forum/topics/difference-between-stubs-and
- http://www.cs.gmu.edu/~mcjunkin/cs112lectures/Stubs.htm
- http://forums.sureshkumar.net/testing-interview-technical-questions/13586-what-difference-between-stub-driver.html
- https://en.wikipedia.org/wiki/Method_stub
