A test plan is usually written whilst the system is being developed. The test plan will contain details of every single thing that needs to be tested.
- Does the system open and close properly?
- Can data be entered?
- Can data be saved?
- Can reports be printed?
- When you do something wrong, does an error message appear?
- Is invalid data rejected? E.g. if you are not allowed to enter an amount above £1,000 on the system then a value of 1,001 should not be accepted (i.e. does the validation work?)
A typical test would contain:
- Details of what is being tested
- The test data to use
- What is expected to happen when the test is performed
Selecting Test Data
To do this, we use three types of test data...
The system should accept it, process it, and we can then check the results that are output to make sure they are correct.
However, the values are chosen to be at the absolute limits of the normal range.
Extreme values are used in testing to make sure that all normal values will be accepted and processed correctly.
The system should reject any abnormal values.
Abnormal values are used in testing to make sure that invalid data does not break the system.
When is the System Tested?
The first phase of testing is done by the designers and engineers who created the system, usually before the system is delivered to the customer.
The test data that is used in this first phase is similar to data that would be used by the actual customer.
The second phase of testing is done after the system has been delivered and installed with the customer.
The data used in the second phase is usually 'live' data - data that is actually part of the customer's business / organisation.
What Happens if the System Fails Some Tests?
If any failures are found, the systems analyst goes back and does some further research, analysis and design to fix these areas.