Since I converted all tests that were included in variables.php into phpunit tests, 3 tests are failing :

• array(false, 'a=3 6;')

  in the test_evaluate_assignments_1 produces a 

  parseerror unexpected '$a' (T_VARIABLE)

• array(false, 'a-'),

  in the test_numerical_formula_2 test produces a

  parse error unexpected '(', expecting ',' or ')'

• array(false, '*a'),

  in the test_numerical_formula_2 test produces a **

  parseerror unexpected '*'

The common point to these failures seems to be that invalid content is send to the evaluate_numerical_expression without being detected and stopped by an exception before. Needs some investigations.