The OCI8 test suite is in ext/oci8/tests. After OCI8 tests are run this directory will also contain logs of any failures.
     Before running PHP's tests, edit details.inc
     and set $user, $password and the $dbase connection string.  The
     OCI8 test suite has been developed using
     the SYSTEM account.  Some tests will fail if
     the test user does not have equivalent permissions.
    
     If Oracle Database Resident Connection Pooling is being
     tested, set $test_drcp to true and ensure the
     connection string uses an appropriate DRCP pooled server.
    
An alternative to editing details.inc is the set environment variables, for example:
    $ export PHP_OCI8_TEST_USER=system
    $ export PHP_OCI8_TEST_PASS=oracle
    $ export PHP_OCI8_TEST_DB=localhost/XE
    $ export PHP_OCI8_TEST_DRCP=FALSE
Next, set any necessary environment for the Oracle database. If you are running PHP on the same machines as Oracle Database, you can run:
    $ . /usr/local/bin/oraenv
With Oracle 11gR2 XE do:
    $ . /u01/app/oracle/product/11.2.0/xe/bin/oracle_env.sh
     Some shells require that php.ini has E in the
     variables_order parameter, for example:
     
    variables_order = "EGPCS"
Run all the PHP tests with:
    $ cd your_php_src_directory
    $ make test
    $ cd your_php_src_directory
    $ make test TESTS=ext/oci8
      When the tests have completed, review any test failures. On slow
      systems, some tests may take longer than the default test
      timeout in run-tests.php.  To correct this,
      set the environment variable TEST_TIMEOUT to
      a larger number of seconds.
    
     On fast machines with a local database configured for light load
     (e.g. Oracle 11gR2 XE) some tests might fail with ORA-12516 or
     ORA-12520 errors.  To prevent this, increase the database
     PROCESSES parameter using the following steps:
    
Connect as the oracle software owner:
    $ su - oracle
Set the necessary Oracle environment with oracle_env.sh or oraenv, as described above.
     Start the SQL*Plus command line tool and
     increase PROCESSES
     
    $ sqlplus / as sysdba
    SQL> alter system set processes=100 scope=spfile
Restart the database:
    SQL> startup force