1.Functional Requirements or usecase document or functional specification.

2.Study of the detailed design of the API to be tested(E Speak and WES)
-Interfaces could Java classes
-Interfaces could be EJB's
-Interfaces could be C++ or VC++ classes
-Interfaces could be CORBA objects
-Interfaces could be peoprietary objects of SAP,SIEBLE,BAAN etc

3.Language in which the interfaces are written(E-Speak &WES)
-Language used in JAVA

4.Choose the language in which client programs to be written(WES)
-client programs could be single class or could client for EJB

5.Choosing of tools to compile client programs(WES)

6.How the parameters are passed to the interface and how the results or return values from the interface are collected for verification(WES)
-The parameter values shall be designed based on the functionality ans passed to the interface using client programs.
-Further testcases can be designed based on the formal test case design techniques
-The results can be collected in the form of XML or Text formats

7.Explore the possibilty using formal test case design techniques for input values of the parameters

8.Cross reference matrix for each interface to be tested

9.Design of test cases, based on target interfaces either single or multiple

10.Design of business scenarios based on the application functional requirements, not based on interface functionality