This "Automation Testing Tutorial" gives you some overview of test automation.

Automation Testing definition:

Software test automation refers to the activities and efforts that are required to automate engineering tasks and operations in a software test process using well-defined strategies and systematic solutions.

Test Automation: Objectives

The major objectives of software test automation

• To free engineers from tedious and redundant manual testing operations.
• To speed up a software testing process, and to reduce software testing cost  and time during a software life cycle.
• To increase the quality and effectiveness of a software test process by achieving pre-defined adequate test criteria in a limited schedule.

Approach Automation Tests:

Automating test input
- Regardless of what the script language is, each is automating  the actions performed
- Each script developed  is an executable test case developed in the language of the particular tool
- Depending on the format of the recorded test, there may also may be a great deal of redundant information contained in the captured script
- Verification points for objects, inputs and outputs are embedded in the script
Replaying the recorded script
-  While replaying the script the test case executes. Differences from the baseline are logged for review

Test Automation: Advantages

- Better use of resources: Entering the same inputs repeatedly is a boring task. Automating helps give greater accuracy as well as improved staff morale, and frees skilled testers to put more effort into  designing better test cases to be run.
 - Consistency and repeatability of tests: Tests that are repeated automatically will be repeated exactly every time (at least the inputs will be). This gives the level of consistency to the tests which is very difficult to achieve manually.
- Reuse of tests.
- Earlier time to market.
- Increased confidence.