org.projog.test

Class ProjogTestParser

java.lang.Object

org.projog.test.ProjogTestParser

public final class ProjogTestParser
extends Object

Parses system test files to produce ProjogTestContent objects.

System test files contain both standard Prolog syntax plus extra detail contained in comments which specify queries and their expected results. The system tests have two purposes:

1. To confirm that the Projog software works as required by comparing the expected results contained in the system tests against the actual results generated when evaluating the queries.
2. To produce the examples contained in the web based Projog manual.

Examples of how system tests can be specified using comments (i.e. lines prefixed with a %) are:

1. Test that that the query ?- test. succeeds once and no attempt will be made to find an alternative solution:

    %TRUE test
    

2. Test that that the query ?- test. succeeds once and will fail when an attempt is made to find an alternative solution:

    %TRUE_NO test
    

3. Test that that the query ?- test. will fail on the first attempt to evaluate it:

    %FAIL test
    

4. Test that that the query ?- test. will succeed three times and there will be no attempt to evaluate it for a fourth time:

    %?- test
    %YES
    %YES
    %YES
    

5. Test that that the query ?- test. will succeed three times and will fail when an attempt is made to evaluate it for a fourth time:

    %?- test
    %YES
    %YES
    %YES
    %NO
    

6. Test that that the query ?- repeat. will succeed three times. The %QUIT markup indicates that after the third attempt then stop testing for alternative solutions, even though they may exist.

    %?- repeat
    %YES
    %YES
    %YES
    %QUIT
    

7. Test that that the query ?- test(X). will succeed three times and there will be no attempt to evaluate it for a fourth time, specifying expectations about variable unification:

    %?- test(X)
    % X=a
    % X=b
    % X=c
    

   The test contains the following expectations about variable unification:
   • After the first attempt the variable X will be instantiated to a.
   • After the second attempt the variable X will be instantiated to b.
   • After the third attempt the variable X will be instantiated to c.
8. Test that that the query ?- test(X,Y). will succeed three times and will fail when an attempt is made to evaluate it for a fourth time, specifying expectations about variable unification:

    %?- test(X,Y)
    % X=a
    % Y=1
    % X=b
    % Y=2
    % X=c
    % Y=3
    %NO
    

   The test contains the following expectations about variable unification:
   • After the first attempt the variable X will be instantiated to a and the variable Y will be instantiated to 1.
   • After the second attempt the variable X will be instantiated to b and the variable Y will be instantiated to 2.
   • After the third attempt the variable X will be instantiated to c and the variable Y will be instantiated to 3.
9. Test that that the query ?- repeat(3), write('hello world'), nl. will succeed three times and there will be no attempt to evaluate it for a fourth time, specifying expectations about what should be written to standard output:

    %?- repeat(3), write('hello world'), nl
    %OUTPUT
    % hello world
    %
    %OUTPUT
    %YES
    %OUTPUT
    % hello world
    %
    %OUTPUT
    %YES
    %OUTPUT
    % hello world
    %
    %OUTPUT
    %YES
    

   The test contains expectations that every evaluation will cause the text hello world and a new-line character to be written to the standard output stream.
10. Test that while evaluating the query ?- repeat(X). an exception will be thrown with a particular message:

     %?- repeat(X)
     %ERROR Expected Numeric but got: NAMED_VARIABLE with value: X
     

11. The following would be ignored when running the system tests but would be used when constructing the web based documentation to include a link to test.html:

     %LINK test
     

Constructor Summary

Constructors

Constructor and Description
ProjogTestParser(File testScript)

Method Summary

Modifier and Type	Method and Description
ProjogTestContent	getNext()
static List<ProjogTestQuery>	getQueries(File testScript)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ProjogTestParser

public ProjogTestParser(File testScript)
                 throws IOException

Throws:

IOException

Method Detail

getQueries

public static List<ProjogTestQuery> getQueries(File testScript)

Throws:

RuntimeException - if script has no tests and no links

getNext

public ProjogTestContent getNext()