1. An apparatus for generating a test script for automatic test execution tools, comprising: a specification file storage section including a computer processor that stores a specification file in which functional specifications of software including a GUI object are described; a property file storage section that stores a property file that maps input variable names in the specification file with object type names; an input/output variable extracting section that analyzes data of the specification file and extracts an input variable name and an output variable name from a computer display screen; and a test-script generating section that generates a test script file that includes the test script, wherein the test script includes instructions that direct one or more of the automatic test execution tools to: search for the property file based on the input variable name extracted by the input/output variable extraction section; acquire an object type name mapped by the input variable name, wherein the test script includes the acquired object type name and input variable name; search the GUI object corresponding to the input variable from the computer display screen where the automatic test execution tools are displayed by the computer display screen when test execution occurs; and compare an expected value corresponding to the output variable with the actual text of the output variable displayed on the computer display screen; and a merging section that obtains a plurality of test scripts from an activity diagram and merges the plurality of test scripts in sequence.