Totally Data-Driven Automated Testing
A White Paper
By
Keith Zambelich
Sr. Software Quality Assurance Analyst
Automated Testing Evangelist
I have been involved in Software Testing and Software Quality Assurance for the past 15 years, and have tested a number of software applications on a variety of platforms. I have also been involved in some form of automated testing or another during this period.
At First Interstate Services Corporation, I was involved in testing Electronic Funds Transfer (EFT) applications written in ACP/TPF. Here I developed the "Transaction Simulation Test Facility", which allowed testers to simulate transactions to and from all of First Interstate’s connections (VISA, Cirrus, Great Western, etc.). This consisted of over 400 programs written in ACP/TPF, and enabled testers to verify all application modifications, including the front-end switching (Tandem) software.
At the Pacific Stock Exchange, I was in charge of testing all Exchange software, including their new PCOAST trading system. I developed and implemented a method of simulating Broker transactions, eliminating the need for live testing with Brokers. This resulted in a greatly improved implementation success rate.
During my employment at Omnikron Systems, Inc. (a software consulting company based in Calabasas, CA) I successfully implemented Automated Testing solutions using Mercury Interactive’s WinRunner® test tool for a variety of companies, including Transamerica Financial Services, J. D. Edwards Co., IBM Canada, PacifiCare Health Systems, and Automated Data Processing (ADP). While at Omnikron Systems, I developed a totally data-driven method of automated testing that can be applied to any automated testing tool that allows scripting.
I have been certified as a WinRunner® Product Specialist (CPS) by Mercury Interactive, Inc. Currently, I am the President and CEO of Automated Testing Specialists, Inc., a consulting firm specializing in the implementation of automated software testing solutions.
The case for automating the Software Testing Process has been made repeatedly and convincingly by numerous testing professionals. Most people involved in the testing of software will agree that the automation of the testing process is not only desirable, but in fact is a necessity given the demands of the current market.
A number of Automated Test Tools have been developed for GUI-based applications as well as Mainframe applications, and several of these are quite good inasmuch as they provide the user with the basic tools required to automate their testing process. Increasingly, however, we have seen companies purchase these tools, only to realize that implementing a cost-effective automated testing solution is far more difficult than it appears. We often hear something like "It looked so easy when the tool vendor (salesperson) did it, but my people couldn’t get it to work.", or, "We spent 6 months trying to implement this tool effectively, but we still have to do most of our testing manually.", or, "It takes too long to get everything working properly. It takes less time just to manually test.". The end result, all too often, is that the tool ends up on the shelf as just another "purchasing mistake".
The purpose of this document is to provide the reader with a clear understanding of what is actually required to successfully implement cost-effective automated testing. Rather than engage in a theoretical dissertation on this subject, I have endeavored to be as straightforward and brutally honest as possible in discussing the issues, problems, necessities, and requirements involved in this enterprise.
Simply put, what is meant by "Automated Testing" is automating the manual testing process currently in use. This requires that a formalized "manual testing process" currently exists in your company or organization. Minimally, such a process includes:
If your current testing process does not include the above points, you are never going to be able to make any effective use of an automated test tool.
So if your "testing methodology" just involves turning the software release over to a "testing group" comprised of "users" or "subject matter experts" who bang on their keyboards in some ad hoc fashion or another, then you should not concern yourself with testing automation. There is no real point in trying to automate something that does not exist. You must first establish an effective testing process.
The real use and purpose of automated test tools is to automate regression testing. This means that you must have or must develop a database of detailed test cases that are repeatable, and this suite of tests is run every time there is a change to the application to ensure that the change does not produce unintended consequences.
An "automated test script" is a program. Automated script development, to be effective, must be subject to the same rules and standards that are applied to software development. Making effective use of any automated test tool requires at least one trained, technical person – in other words, a programmer.
Automated testing is expensive (contrary to what test tool vendors would have you believe). It does not replace the need for manual testing or enable you to "down-size" your testing department. Automated testing is an addition to your testing process. According to Cem Kaner, in his paper entitled "Improving the Maintainability of Automated Test Suites" (www.kaner.com), it can take between 3 to 10 times as long (or longer) to develop, verify, and document an automated test case than to create and execute a manual test case. This is especially true if you elect to use the "record/playback" feature (contained in most test tools) as your primary automated testing methodology. Record/Playback is the least cost-effective method of automating test cases.
Automated testing can be made to be cost-effective, however, if some common sense is applied to the process:
Every automated test tool vendor will tell you that their tool is "easy to use" and that your non-technical user-type testers can easily automate all of their tests by simply recording their actions, and then playing back the recorded scripts. This one statement alone is probably the most responsible for the majority of automated test tool software that is gathering dust on shelves in companies around the world. I would just love to see one of these salespeople try it themselves in a real-world scenario. Here’s why it doesn’t work:
After about 2 to 3 months of this nonsense, the tool gets put on the shelf or buried in a desk drawer, and the testers get back to manual testing. The tool vendor couldn’t care less – they are in the business of selling test tools, not testing software.
Now that we’ve eliminated Record/Playback as a reasonable long-term automated testing strategy, let’s discuss some methodologies that I (as well as others) have found to be effective for automating functional or system testing for most business applications
The main concept behind the "Functional Decomposition" script development methodology is to reduce all test cases to their most fundamental tasks, and write User-Defined Functions, Business Function Scripts, and "Sub-routine" or "Utility" Scripts which perform these tasks independently of one another. In general, these fundamental areas include:
In order to accomplish this, it is necessary to separate Data from Function. This allows an automated test script to be written for a Business Function, using data-files to provide the both the input and the expected-results verification. A hierarchical architecture is employed, using a structured or modular design.
The highest level is the Driver script, which is the engine of the test. The Driver Script contains a series of calls to one or more "Test Case" scripts. The "Test Case" scripts contain the test case logic, calling the Business Function scripts necessary to perform the application testing. Utility scripts and functions are called as needed by Drivers, Main , and Business Function scripts.
Perform initialization (if required), then call the Test Case Scripts in the desired order.
Perform the application test case logic using Business Function Scripts
Perform specific Business Functions within the application;
Perform application specific tasks required by two or more Business scripts;
General, Application-Specific, and Screen-Access Functions;
Note that Functions can be called from any of the above script types.
Example:
The following steps could constitute a "Post a Payment" Test Case:
1. Access Payment Screen from Main Menu
2. Post a Payment
3. Verify Payment Updates Current Balance
4. Return to Main Menu
5. Access Account Summary Screen from Main Menu
6. Verify Account Summary Updates
7. Access Transaction History Screen from Account Summary
8. Verify Transaction History Updates
9. Return to Main Menu
A "Business Function" script and a "Subroutine" script could be written as follows:
Payment:
· Start at Main Menu
· Invoke a "Screen Navigation Function" to access the Payment Screen
· Read a data file containing specific data to enter for this test, and input the data
· Press the button or function-key required to Post the payment
· Read a data file containing specific expected results data
· Compare this data to the data which is currently displayed (actual results)
· Write any discrepancies to an Error Report
· Press button or key required to return to Main Menu or, if required, invoke a "Screen Navigation Function" to do this.
Ver-Acct (Verify Account Summary & Transaction History):
· Start at Main Menu
· Invoke a "Screen Navigation Function" to access the Account Summary
· Read a data file containing specific expected results data
· Compare this data to the data which is currently displayed (actual results)
· Write any discrepancies to an Error Report
· Press button or key required to access Transaction History
· Read a data file containing specific expected results data
· Compare this data to the data which is currently displayed (actual results)
· Write any discrepancies to an Error Report
· Press button or key to return to Main Menu or, invoke a "Screen Navigation Function"
The "Business Function" and "Subroutine" scripts invoke "User Defined Functions" to perform navigation. The "Test Case" script would call these two scripts, and the Driver Script would call this "Test Case" script some number of times required to perform all the required Test Cases of this kind. In each case, the only thing that changes are the data contained in the files that are read and processed by the "Business Function" and "Subroutine" scripts.
Using this method, if we needed to process 50 different kinds of payments in order to verify all of the possible conditions, then we would need only 4 scripts which are re-usable for all 50 cases:
1. The "Driver" script
2. The "Test Case" (Post a Payment & Verify Results) script
3. The "Payment" Business Function script
4. The "Verify Account Summary & Transaction History" Subroutine script
If we were using Record/Playback, we would now have 50 scripts, each containing hard-coded data, that would have to be maintained.
This method, however, requires only that we add the data-files required for each test, and these can easily be updated/maintained using Notepad or some such text-editor. Note that updating these files does not require any knowledge of the automated tool, scripting, programming, etc. meaning that the non-technical testers can perform this function, while one "technical" tester can create and maintain the automated scripts.
It should be noticed that the "Subroutine" script, which verifies the Account Summary and Transaction History, can also be used by other test cases and business functions (which is why it is classified as a "Subroutine" script rather than a "Business Function" script) – Payment reversals, for example. This means that if we also need to perform 50 "payment reversals", we only need to develop three additional scripts.
1. The "Driver" script
2. The "Test Case" (Reverse a Payment & Verify Results) script
3. The "Payment Reversal" Business Function script
Since we already had the original 4 scripts, we can quickly clone these three new scripts from the originals (which takes hardly any time at all). We can use the "Subroutine" script as-is without any modifications at all.
If different accounts need to be used, then all we have to do is update the Data-Files, and not the actual scripts. It ought to be obvious that this is a much more cost-effective method than the Record/Playback method.
Advantages:
1. Utilizing a modular design, and using files or records to both input and verify data, reduces redundancy and duplication of effort in creating automated test scripts.
2. Scripts may be developed while application development is still in progress. If functionality changes, only the specific "Business Function" script needs to be updated.
3. Since scripts are written to perform and test individual Business Functions, they can easily be combined in a "higher level" test script in order to accommodate complex test scenarios.
4. Data input/output and expected results is stored as easily maintainable text records. The user’s expected results are used for verification, which is a requirement for System Testing.
5. Functions return "TRUE" or "FALSE" values to the calling script, rather than aborting, allowing for more effective error handling, and increasing the robustness of the test scripts. This, along with a well-designed "recovery" routine, enables "unattended" execution of test scripts.
Disadvantages:
1. Requires proficiency in the Scripting language used by the tool (technical personnel);
2. Multiple data-files are required for each Test Case. There may be any number of data-inputs and verifications required, depending on how many different screens are accessed. This usually requires data-files to be kept in separate directories by Test Case.
3. Tester must not only maintain the Detail Test Plan with specific data, but must also re-enter this data in the various required data-files.
4. If a simple "text editor" such as Notepad is used to create and maintain the data-files, careful attention must be paid to the format required by the scripts/functions that process the files, or script-processing errors will occur due to data-file format and/or content being incorrect.
This method uses the actual Test Case document developed by the tester using a spreadsheet containing special "Key-Words". This method preserves most of the advantages of the "Functional Decomposition" method, while eliminating most of the disadvantages. In this method, the entire process is data-driven, including functionality. The Key Words control the processing.
Consider the following example of our previous "Post a Payment" Test Case:
COLUMN 1 Key_Word |
COLUMN 2 Field/Screen Name |
COLUMN 3 Input/Verification Data |
COLUMN 4 Comment |
COLUMN 5 Pass/Fail |
|
|
|
|
|
Start_Test: |
Screen |
Main Menu |
Verify Starting Point |
|
|
|
|
|
|
Enter: |
Selection |
3 |
Select Payment Option |
|
|
|
|
|
|
Action: |
Press_Key |
F4 |
Access Payment Screen |
|
|
|
|
|
|
Verify: |
Screen |
Payment Posting |
Verify Screen accessed |
|
|
|
|
|
|
Enter: |
Payment Amount |
125.87 |
Enter Payment data |
|
|
Payment Method |
Check |
|
|
|
|
|
|
|
Action: |
Press_Key |
F9 |
Process Payment |
|
|
|
|
|
|
Verify: |
Screen |
Payment Screen |
Verify screen remains |
|
|
|
|
|
|
Verify_Data: |
Payment Amount |
$ 125.87 |
Verify updated data |
|
|
Current Balance |
$1,309.77 |
|
|
|
Status Message |
Payment Posted |
|
|
|
|
|
|
|
Action: |
Press_Key |
F12 |
Return to Main Menu |
|
|
|
|
|
|
Verify: |
Screen |
Main Menu |
Verify return to Menu |
|
Each of the "Key Words" in Column 1 causes a "Utility Script" to be called which processes the remaining columns as input parameters in order to perform specific functions. Note that this could also be run as a manual test. The test engineer must develop and document the test case anyway – why not create the automated test case at the same time?
The data in red indicates what would need to be changed if one were to copy this test case to create additional tests.
How in the World Does This Work?
Architecture
The architecture of the "Test Plan Driven" method appears similar to that of the "Functional Decomposition" method, but in fact, they are substantially different:
Advantages:
This method has all of the advantages of the "Functional Decomposition" method, as well as the following:
10. The Detail Test Plan can be written in Spreadsheet format containing all input and verification data. Therefore the tester only needs to write this once, rather than, for example, writing it in Word, and then creating input and verification files as is required by the "Functional Decomposition" method.
11. Test Plan does not necessarily have to be written using Excel. Any format can be used from which either "tab-delimited" or "comma-delimited" files can be saved (e.g. Access Database, etc.).
12. If "utility" scripts can be created by someone proficient in the Automated tool’s Scripting language prior to the Detail Test Plan being written, then the tester can use the Automated Test Tool immediately via the "spreadsheet-input" method, without needing to learn the Scripting language. The tester need only learn the "Key Words" required, and the specific format to use within the Test Plan. This allows the tester to be productive with the test tool very quickly, and allows more extensive training in the test tool to be scheduled at a more convenient time.
13. If the Detail Test Plan already exists in some other format, it is not difficult to translate this into the "spreadsheet" format.
14. After a number of "generic" Utility scripts have already been created for testing an application, we can usually re-use most of these if we need to test another application. This would allow the organization to get their automated testing "up and running" (for most applications) within a few days, rather than weeks.
Disadvantages:
15. Development of "customized" (Application-Specific) Functions and Utilities requires proficiency in the tool’s Scripting language. Note that this is also true of the "Functional Decomposition" method, and, frankly of any method used including "Record/Playback".
16. If application requires more than a few "customized" Utilities, this will require the tester to learn a number of "Key Words" and special formats. This can be time-consuming, and may have an initial impact on Test Plan Development. Once the testers get used to this, however, the time required to produce a test case is greatly improved.
Cost-Effectiveness:
In the example we gave using the "Functional Decomposition" method, it was shown that we could use previously created "Test Case" and "Business Function" scripts to create scripts for additional Test Cases and Business Functions. If we have 100 Business Functions to test, this means that we must create a minimum of 200 scripts (100 Test Case scripts, and 100 Business Function scripts).
Using the "Test Plan Driven" method, I currently am using 20 Utility scripts, that I have been able to use in every single automated testing engagement that I have been sent on. Let us examine what it takes on an average for me to walk into a company, and implement Automated Testing:
Depending on the complexity of the application, and how well the test tool works with the application, this process normally takes me no more than 3 days – 5 days is worst-case. With this "proof-of-concept" completed, if we are then contracted to do the job, it usually takes 2 or 3 weeks to develop the majority of the application-specific functions, and application-specific versions of the "utility" scripts. Naturally, if the application is quite complex, this process will take longer. At this point, testers can be trained to create the spreadsheet data (usually takes about a week) and then they are in business. It also takes about a week to train the "test tool technician" to use this methodology, provided that this person is a relatively competent programmer and has already been sufficiently trained by the tool vendor in the use of the tool.
What this demonstrates is that an organization can implement cost-effective automated testing if they go about it the right way.
Preparation is the Key:
The situation described above is pretty much an "ideal scene". It assumes that adequate preparations have been made by the organization before beginning the testing automation process. This is rarely the case, however. If adequate preparations have not been made, then the "ramp-up" time required is increased dramatically. What then, does an organization do to prepare themselves for this effort?
One of the main reasons organizations fail at implementing automated testing (apart from getting mired down in the "record/playback" quagmire) is that most testers do not welcome what they perceive as a fundamental change to the way they are going to have to approach their jobs. Typically, decisions as to what tool to use and how to implement it are made by management, often without consulting the people who are actually doing the testing, and who are now going to have to cope with all of this. This usually meets with a great deal of resistance from the testers, especially when management does not have a clearly defined idea of how to implement these changes effectively. Let us examine some concerns that might be expressed by testers, and some answers to these:
This is not even remotely true. The automated testing tool is just another tool that will allow testers to do their jobs better by:
The testers are still going to have to perform tests manually for specific application changes. Some of these tests may be automated afterward for regression testing.
If the "test-plan-driven" method (described above) is used, the testers will not have to learn how to use the tool at all if they don’t want to. All that they have to learn is a different method of documenting the detailed test cases, using the key-word/spreadsheet format. It is not that different from what they are doing currently, and takes only a few hours to learn.
Perhaps, but as we have already discussed, they will not have to use it. What will be required is that a "Test Tool Specialist" will need to be hired and trained to use the tool. This can either be a person who is already an expert with the particular tool, or can be a senior-level programmer who can easily be trained to use it. Most test-tool vendors offer training courses.
The "test-plan-driven" testing method will eliminate most of the testers’ concerns regarding automated testing. They will perform their jobs exactly as they do now. They will only need to learn a different method of documenting their test cases.
One area that organizations desiring to automate testing seem to consistently miss is the staffing issue. Automated test tools use "scripts" which automatically execute test cases. As I mentioned earlier in this paper, these "test scripts" are programs. They are written in whatever scripting language the tool uses. This might be C++ or Visual Basic, or some language unique to the test tool. Since these are programs, they must be managed in the same way that application code is managed.
To accomplish this, a "Test Tool Specialist" or "Automated Testing Engineer" or some such position must be created and staffed with at least one senior-level programmer. It does not really matter what languages the programmer is proficient in. What does matter, is that this person must be capable of designing , developing, testing, debugging, and documenting code. More importantly, this person must want to do this job – most programmers want nothing to do with the Testing Department. This is not going to be easy, but it is nonetheless absolutely critical. In addition to developing automated scripts and functions, this person must be responsible for:
It is often useful to hire a contractor (like me) who knows how to set this all up, help train the "Automation Engineer", and the testing staff, and basically get things rolling. In my experience, this can take from two to three weeks, or as long as two to three months, depending on the situation. In any case, it should be a short-term assignment, and if you find someone who really knows what they’re doing, it will be well worth it.
It is worth noting that no special "status" should granted to the automation tester(s). The non-technical testers are just as important to the process, and favoritism toward one or the other is counter-productive and should be avoided. Software Testing is a profession, and as such, test engineers should be treated as professionals. It takes just as much creativity, brain power, and expertise to develop effective, detailed test cases from business and design specifications as it does to write code. I have done both, and can speak from experience.