Isolation

The isolation level of a test case varies based on the changes that the test case
will make to the data. Each test case could have different needs for isolation
based on what data it will change. The Unit Test framework provides four test
suite base classes that provide different levels of isolation. The following table
describes the test suites by the level of isolation that they provide.

Test suite class	Description
SysTestSuite	Default test suite. No isolation.
SysTestSuiteCompanyIsolate Class	Constructs an empty company account for each test class. All test methods on the class are run within the company, then it is deleted.
SysTestSuiteCompanyIsolate Method	Constructs an empty company account for each test method, and then deletes it at the end of the method.
SysTestSuiteTTS	Wraps each test method in a transaction. After the method is complete, the transaction is aborted. Note: Tests that need to commit data will not work in this suite. Also, the ParmExceptionExpected exception is not supported in this suite.
SysTestSuiteCompIsolate ClassWithTts	This is a combination of SysTestSuiteCompanyIsolateClass and SysTestSuiteTTS.

To apply a specific test suite to a test class, override the createSuite method on
the test class, and return an object of the type of the suite required.

The following example demonstrates how a test suite can be applied to a test
class.

1 2 3 4 5

class SysTestSuite createSuite() { // Isolation level: construct a company account for the entire test class. return new SysTestSuiteCompanyIsolateClass(this); }

Best Regards,
Hossein Karimi