#!/usr/bin/env python
"""Pytest is a testing interpreter for Python; see man 1 pytest for details.
"""

##
# Set aside a clean testing environment.
##

import sys
__modules__ = sys.modules.copy()
# del __modules__['sys'] # afaict this doesn't actually unload the module :/
__globals__ = globals()
__locals__  = locals()



##
# Now proceed as normal.
##

import fnmatch
import os

import PyTest

##
# Set up some test runners.
##

def test_one(filename, report_buffer=None):

    """Given a filename, test and report on that single file.

    Only non-passing tests will be detailed in the report. An optional
    report_buffer may be passed in to capture the report output.

    """

    heisenberg = PyTest.Observer()
    heisenberg.start_timer()

    # read in the file to test and mix in our testing framework
    original = file(filename).read()
    interpolated = PyTest.Interpolator.interpolate(original)

    # set up the lab environment and run the test
    sys.path[0] = os.curdir
    sys.modules = __modules__
    __globals__['__pytest__'] = sys.stdout = heisenberg
    heisenberg.run(filename, interpolated, __globals__, __locals__)

    heisenberg.stop_timer()

    if report_buffer is not None:
        # we are being run as part of a test suite, so send our report to
        # the main report buffer ...
        if (heisenberg.failures + heisenberg.exceptions) > 0:
            # but only if there is something to report
            sys.stdout = report_buffer
            heisenberg.report()
            sys.stdout = sys.__stdout__
        else:
            # nothing to report, so just be quiet
            pass
    else:
        # otherwise send the report to the standard output
        sys.stdout = sys.__stdout__
        heisenberg.report()

    return { 'passes'       : heisenberg.passes
           , 'failures'     : heisenberg.failures
           , 'exceptions'   : heisenberg.exceptions
           , 'nontest_excs' : heisenberg.nontest_excs
            }


def test_all(filenames):

    """Given a list of filenames, test and report on all the files.

    Only files with non-passing tests will be detailed in the report.

    """

    # determine the heading for our report
    if len(filenames) == 1:
        file_files = 'file'
    else:
        file_files = 'files'
    heading = 'EXECUTIVE SUMMARY: %s %s' % (len(filenames), file_files)

    # 'management' -- cause all it cares about is the executive summary
    management = PyTest.Observer()
    management.start_timer()

    for filename in filenames:

        results = test_one(filename, management)

        # update the executive summary
        management.passes += results['passes']
        management.failures += results['failures']
        management.exceptions += results['exceptions']
        management.nontest_excs += results['nontest_excs']

    management.stop_timer()
    management.report(heading)


if __name__ == '__main__':

    ##
    # Parse the command line argument.
    ##

    arg = sys.argv[1:2]
    if not arg:
        print __doc__
        raise SystemExit
    else:
        fnpattern = arg[0]
        filenames = fnmatch.filter(os.listdir('.'), fnpattern)


    ##
    # Pick and run a test runner.
    ##

    if len(filenames) == 0:
        print '<%s> did not match any files in the current directory' % fnpattern
        sys.exit(0)
    elif len(filenames) > 1:
        test_all(filenames)
    elif filenames[0] == fnpattern:
        test_one(filenames[0])
    else:
        test_all(filenames)