Specification is important – this statement is clear to everyone. A widely used product, technology or language without a specification is useless. A specification without a testsuite is dangerous. A testsuite without markup and tests is impossible. This process is quite complex. However there are ways to simplify the markup stage.
As for Java Language Specification (JLS) and (JVMS) they are written in FrameMaker. Afterwards spec is exported to html and pdf. The markup is embedded into html version. My opinion is that markup information should be placed into (or connected with) the origin text. In our case it is FrameMaker document. I’m not sure that this is possible at all, but my guess it is. If not, maybe FrameMaker is not the best solution. As a result we will significantly reduce the amount of time and effort needed for transferring old markup and marking up new text. Moreover during writing the next revision of spec the auther together with tck team should markup all chenged and new assertions. I’d say the best way is when the spec writing and the markup processes are done at the same time. It is reasonable for the auther to point out the test developers what statements should be tested.
It is very important to have a good process while writing the test suite. I will talk about the one that was used for JLS.
As mentioned before the final product is the number of tests. There is a relation between the tests and the specification. The assertion-driven process gives an idea of what each group of tests actually checks in the specification. Using this relation the developer can calculate the coverage, get the list of assertions on which the tests were not written, etc.
Assertion is a statement from a specification that can be tested. And the first step is to identify all assertions in the specification. After that the developer can write tests.
Example of assertions from the Java Language Specification:
A compile-time error occurs if the same modifier appears more than once in an interface declaration.
The binary name of a member type consists of the binary name of its immediately enclosing type, followed by $, followed by the simple name of the member.
A continue statement may occur only in a while, do, or for statement.
There could be many statements that are non-testable or involve uncertainty. Sometimes such statements include words like “possible” or “maybe”. It is not true that if a sentence has a word “may” it is not testable, but usually it is so.
Examples of non-testable statements:
We do not recommend such “mixed notation” for array declarations.
Situations where the class of an object is not statically known may lead to run-time type errors.
If, however, evaluation of an expression throws an exception, then the expression is said to complete abruptly.
There are many discussions and disputes about assertions. Some say that examples should not be treated as assertions. Others say that each statement is an assertions and there are two kinds of them: testable and non-testable. My personal opinion is that an assertion is certainly something testable. And in most cases examples are assertions just because the test can be written checking the particular example.
The process of identifying assertions in the specification is called markup. There are many approaches. But in any case the user must be able to get information on whether the statement is an assertion and somehow distinguish one assertion from another. There could be a separate repository with mapping of assertions and their id’s to statements. I like the idea of integrating the markup into the specification. This approach was chosen for the language area of the Java SE test suite. The JLS was written in FrameMaker. With export mechanisms the PDF and HTML versions were created. The html version was used during the creation of the test suite.
In JLS and JLS 2 some special anchors identified the beginning and the end of an assertion. Additional information was the assertionID and short summary of the statement. The end anchor was an image and a link to the test. The html view and the code view are shown on the corresponding illustrations. The assertion id’s are arr033, arr034, arr020, etc.
The general idea can be described as:
<a name=assertionID><!– shord description as html comment –>
assertion statement here
<img src=”pics/assert.gif”><a href=”path to test”>test ID which is the same as assertion ID</a>
If seperate statements in different parts of specification are tested by one test the first tag will be something like arr033_0, arr033_1, arr033_2.
This kind of architecture was used for JLS and JLS 2. It was slightly modified for JLS3, but the main idea was kept. I know some examples of approaches with non-static assertion IDs kept in a separate repository, where ID is some hash-value calculated based on the content. For several reasons it showed up to be not a very good solution. There is always a hard process migrating to the new version of the specification. But in my opinion it is much easier with the static ID’s embedded into the specification.
I do read weblogs. I started reading them much more. Why am I doing this? Well.. I’m a believer that information sharing does make other people’s work more fun. And not only work, but people lives overall. Sharing knowledge and thoughts is a big step towards building communities. Weblog allows to publish thoughts, opinions, ideas, concerns to the readers. While the readers can open a dialog on a discussed topic using comments.
I wanted to create my personal weblog long ago, but I guess I finally made it.
I work as a software engineer in a group that creates a very important product. This product is not as well-known as Java or Solaris. I’d say most of software engineers in this huge world do not know about it. However without this product there will be no Java as we know it. At least Java will not be as good, as popular and as wide-spread as it is and as we want it to be. Without this product there will be no WORA (write once run anywhere). Yes, I’m talking about compatibility. And the product is a TCK (Technology Compatibility Kit) for Java. In two words TCK is a test suite, which makes sure that implementations of Java conform to the specification. My group works under several TCK’s. But the main one is for Java SE platform.
There are several different areas in JCK (TCK for Java SE): API, Java Language and VM.
My area that I work on for more than 2 years is "Java Language". I write compiler and runtime tests to make sure that Sun’s and other companies’ implementations behave exactly as it is said in the JLS (Java Language Specification).
In this weblog I will try to share my knowledge, my opinions and thoughts regarding my work.
PS: English is not my native language. That’s why I would like to apologize for possible mistakes (I’m sure there are many of them already) and weird sentances in my weblog. I’ll try to do my best.
Specification is important – this statement is clear to everyone. A widely used product, technology or language without a specification is useless. A specification without a testsuite is dangerous. A testsuite without markup and tests is impossible. This process is quite complex. However there are ways to simplify the markup stage.
