Instrumenting an Executable File

LiveCoverage uses a patented technology which inserts probes into your program as it is running to monitor test coverage. As a result, it is not necessary to "instrument" your program in the way other test coverage tools would.

There is still an option to instrument your program. But with LiveCoverage, this refers only to adding a tiny slice of code that "wakes up" LiveCoverage whenever your program starts running. Without it, LiveCoverage must launch your program (at least indirectly) to monitor test coverage.

Tips on Choosing

If you will be running tests manually or semi-manually, it is usually simplest to have LiveCoverage start your program for you without using instrumentation.

If you have a fully automated test suite of significant complexity, then instrumentation is the surest way to get test coverage working quickly.

Here are the pros and cons of using and not using instrumentation:

Using Instrumentation

Advantages

• No changes are needed in any part of your test process. Simply start up LiveCoverage's test coverage monitoring, then start your tests. Each time your program is run, LiveCoverage will automatically "hook up" and start monitoring it for test coverage.
• If your program is launched by the system, as in the case of an out-of-process COM server, LiveCoverage will still monitor it.

Disadvantages

• The instrumentation process modifies your executable file. This essentially creates a new "version" of your program that must be kept distinct from a version you would release to your users.
• LiveCoverage will not know when your testing is complete. It will continue to monitor for test coverage until it is stopped manually.
• The executable file is never enlarged by instrumentation; the added code is fit into unused space in the file. This leaves at least the theoretical possibility that a file cannot be instrumented because there isn't enough unused space within it.
• Only .EXE files can be instrumented, not .DLL files. All DLL's running with an instrumented EXE are automatically monitored for test coverage. However, a DLL running with an uninstrumented EXE will not be monitored.

No Instrumentation

Advantages

• There are no modifications made to your executable files, and no additional "versions" to keep track of.
• Because LiveCoverage starts the test process, it knows when it finishes. At completion, LiveCoverage will automatically stop coverage monitoring and save the results.

Disadvantages

• LiveCoverage must launch your program, at least indirectly. LiveCoverage can monitor through a chain of launches, such as a batch file launching a VB test driver which repeatedly launches your program. However, each step in the chain must be a 32-bit program. For example, the Windows 95/98 command line processor COMMAND.COM is a 16-bit program, and LiveCoverage cannot monitor any program it might launch. This could require a change in your testing process.
• An out-of-process COM server is launched by the system, not LiveCoverage, and cannot be monitored without instrumentation.

Once You've Chosen

Once you have chosen whether or not to use instrumentation, you must set the project's properties accordingly. By default, a new project will not be set to use instrumentation.

Use the Properties command on the Test menu to display the project's Properties dialog. The dialog contains one page for the Project Properties, plus one page of Executable File Properties for each executable file in the project. Make the following changes:

To Use Instrumentation

• For each .EXE file in the project, use the tab to select the Executable File Properties page. Then check the Instrument check box on the page. Note that this box is disabled for .DLL files.
• On the Project Properties page, check the Listen for instrumented executables check box.
• Also on the Project Properties page, delete any text in the Command Line text box.

Not Using Instrumentation

• On the Project Properties page, set the Command Line text box to the program you want LiveCoverage to launch, including any command line parameters. By default, LiveCoverage will have filled in the name of one your executable files.
• Also on the Project Properties page, fill in the Initial Folder text box with the initial folder for the program being launched. If this is left blank, the program will launch in the folder of its executable file.