I am reading "The Pragmatic Programmer" . The book has the following paragraph
Dave once worked on an international telex switch. Quite understandably, the client demanded an exhaustive test specification and required that the software pass all tests on each delivery. To ensure that the tests accurately reflected the specification, the team generated them programmatically from the document itself. When the client amended their specification, the test suite changed automatically. Once the team convinced the client that the procedure was sound, generating acceptance tests typically took only a few seconds.
I am curious to know how he created tests from specification . What format was the specification in ? How to write a program that will automatically read the specification and write test cases. Have I misunderstood the above paragraph ?