Self-testing code is software that incorporates built-in tests (see test-first development).^[1][2]

Perl packages will run their self tests when they are installed using CPAN. This ensures that they run successfully in the local environment. (There is also a testing community that tests new packages and updated packages on many different platforms.)

In Java, to execute a unit test from the command line, a class can have methods like the following.

// Executing <code>main</code> runs the unit test.
publicstaticvoidmain(String[]args){
test();
}

staticvoidtest(){
assertfoo==bar;
}

To invoke a full system test, a class can incorporate a method call.

publicstaticvoidmain(String[]args){
test();
TestSuite.test();// invokes full system test
}

In addition, Java has some Jupiter API libraries for self-testing code. assert can be used in various ways such as assert equals, which checks if the given variable is equal to the value given.

@Test
voidcheckplayer(){
Boardboard=newBoard(10);
board.addplayer(1);
intcheck=board.getCurrentPlayer(1);
assertEquals(1,check);

}

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