| # Automatic Python regression test. |
| # |
| # Some essential parts of the Python interpreter are tested by the module |
| # 'testall'. (Despite its name, it doesn't test everything -- that would |
| # be a truly Herculean task!) When a test fails, 'testall' raises an |
| # exception. When all tests succeed, it produces quite a lot of output. |
| # |
| # For a normal regression test, this output is never looked at unless |
| # something goes wrong. Thus, it would be wise to suppress the output |
| # normally. This module does that, but it doesn't just throw the output |
| # from 'testall' away -- it compares it with the output from a previous |
| # run. If a difference is noticed it raises an exception; if all is well, |
| # it prints nothing except 'All tests OK.' at the very end. |
| # |
| # The output from a previous run is supposed to be in a file 'testall.out' |
| # somewhere on the search path for modules (sys.path, initialized from |
| # $PYTHONPATH plus some default places). |
| # |
| # Of course, if the normal output of the tests is changed because the |
| # tests have been changed (rather than a test producing the wrong output), |
| # 'autotest' will fail as well. In this case, run 'testall' manually |
| # and direct its output to 'testall.out'. |
| # |
| # The comparison uses (and demonstrates!) a rather new Python feature: |
| # program output that normally goes to stdout (by 'print' statements |
| # or by writing directly to sys.stdout) can be redirected to an |
| # arbitrary class instance as long as it has a 'write' method. |
| |
| import os |
| import sys |
| |
| # Function to find a file somewhere on sys.path |
| def findfile(filename): |
| for dirname in sys.path: |
| fullname = os.path.join(dirname, filename) |
| if os.path.exists(fullname): |
| return fullname |
| return filename # Will cause exception later |
| |
| # Exception raised when the test failed (not the same as in test_support) |
| TestFailed = 'autotest.TestFailed' |
| |
| # Class substituted for sys.stdout, to compare it with the given file |
| class Compare: |
| def init(self, filename): |
| self.fp = open(filename, 'r') |
| return self |
| def write(self, data): |
| expected = self.fp.read(len(data)) |
| if data <> expected: |
| raise TestFailed, \ |
| 'Writing: '+`data`+', expected: '+`expected` |
| def close(self): |
| self.fp.close() |
| |
| # The main program |
| def main(): |
| import sys |
| filename = findfile('testall.out') |
| real_stdout = sys.stdout |
| try: |
| sys.stdout = Compare().init(filename) |
| import testall |
| finally: |
| sys.stdout = real_stdout |
| print 'All tests OK.' |
| |
| main() |