I am generally not a big fan of static test data. I do know that in the proper context static test data can provide some value. Of course we should be aware of the common problems with files of static test data or (even worse) hard coded test data in a test case. Some problems with static test data include:
- Stagnation – static test data may add some initial value, but over time simply reusing the same test data over and over in a test diminishes the value of that test. For example, retesting the same name strings in a first name input textbox is not providing any new information if those ‘static’ names worked in the previous build and the underlying functionality has not changed.
- Contextual blindness – sometimes we have files of static test data that was identified as “problematic” in one situation (context), so we reuse the “problematic” test data regardless of the context. In 1995 I wrote a white paper on “problematic double-byte encoded characters (DBCS) explaining why each code point was problematic in a given context. For example, a Japanese character that began with a 0x5C trail-byte might be problematic in a filename on an ANSI based system that parsed characters by bytes instead of wide bytes. This is not true on Windows systems where the default encoding is the Unicode transformation format of UTF-16. However, some people continue to use obsolete DBCS problem characters perhaps because they don’t fully understand the underlying contextual differences between ANSI based encodings and Unicode.
Perhaps on the opposite end of the test data spectrum is random test data. Many of you that read this blog or have heard me speak know that I am a big proponent of parameterized random test data generation. Parameterization allows us to better model our test data. I know that even parameterized random data can be crafted to be representative of real data, but it is not “real” data.
But, there may be a happy medium between static test data and random test data. And, best of all it is abundantly available. One of the best sources for (especially non-English) test data comes from sources that most of us already use on a daily basis. The test data source I speak of are social networks.
I have met many wonderful people from around the world both in person and virtually, and stayed in contact with many of them. Last year while keynoting at the first software testing conference in Vietnam (VistaCon 2010) I was privileged to meet my dear friend Thuyen, who helped organize the conference. Since the conference we have stayed in contact via email and Facebook. When she posts on Facebook it is usually in Vietnamese. Since I don’t (yet) read Vietnamese I use Bing Translator to help me figure out the comment.
Last week she had an entry on her Facebook wall that began “Tối nay vô tình nghe trên TV 1 bài hát mà giai điệu…” So, I copied the entry and opened Bing Translator to translate the entry.
Many of you will quickly notice the strange anomaly in the translation. I initially thought that this service might be incrementing this numeric value for some reason, but when I changed the number value to 2 the number 2 displayed in the translated string. I tried various other numbers and quickly discovered that 6 incremented to the number 7, 8 decremented to 7, and 9 decremented to the number 3. I didn’t see a clear pattern here so I thought this might be an issues resulting from parsing a particular sequence of characters.
So, I modified different parts of the string (removed words) to narrow down the problem. I found the string “tình nghe trên TV 1 bài hát mà giai điệu” contained the problematic sequence. Removing any ‘word’ from this string displayed the translated string with a number of 1, with the exception of 1 word. Removing the word “nghe” from the above string resulted in the translation illustrated below.
But, the purpose of this post is not to illustrate this particular bug, but to give you ideas of how we can use social network feeds in our testing. People around the world use social networks and you can find “real world” strings in various languages that you can use as test data in various contexts. Most of the time this ‘test data’ will not likely result in a bug; but sometimes it can reveal interesting issues. Best of all, strings taken from social networks are not some manufactured static or random test data. Using strings copied from social networks is about as “real world” as we can get…this is the “data” from our customers.