tests/basic_test_result.py

run-tests: stop ignoring venv-installed packages

This will allow test dependencies to be installed within a venv, instead of
tampering with sys/user sites.  One thing to note here is that the `VIRTUAL_ENV`
path takes precedence over system-site, unlike when run directly with an
activated `venv`.  For example, `sys.path` as viewed from a feature test in
`hghave.py`, when running `hghave vcr` directly with an activated `venv`:

    sys.path: [
        '/home/jenkins/hg-committed/tests',
        '/usr/lib/python38.zip',
        '/usr/lib/python3.8',
        '/usr/lib/python3.8/lib-dynload',
        '/home/jenkins/test_venv/lib/python3.8/site-packages'
    ]

vs `sys.path` from the same feature test, when run by `run-tests.py` with this
change:

    sys.path: [
        '/home/jenkins/hg-committed/tests',
        '/home/jenkins/hg-committed',
        '/home/jenkins/hg-committed/tests',
        '/home/jenkins/test_venv/lib/python3.8/site-packages',
        '/usr/lib/python38.zip',
        '/usr/lib/python3.8',
        '/usr/lib/python3.8/lib-dynload',
        '/home/jenkins/.local/lib/python3.8/site-packages',
        '/usr/local/lib/python3.8/dist-packages',
        '/usr/lib/python3/dist-packages'
    ]

import sys
import unittest

if sys.version_info[0] < 3:
    base_class = unittest._TextTestResult
else:
    base_class = unittest.TextTestResult


class TestResult(base_class):
    def __init__(self, options, *args, **kwargs):
        super(TestResult, self).__init__(*args, **kwargs)
        self._options = options

        # unittest.TestResult didn't have skipped until 2.7. We need to
        # polyfill it.
        self.skipped = []

        # We have a custom "ignored" result that isn't present in any Python
        # unittest implementation. It is very similar to skipped. It may make
        # sense to map it into skip some day.
        self.ignored = []

        self.times = []
        self._firststarttime = None
        # Data stored for the benefit of generating xunit reports.
        self.successes = []
        self.faildata = {}

    def addFailure(self, test, reason):
        print("FAILURE!", test, reason)

    def addSuccess(self, test):
        print("SUCCESS!", test)

    def addError(self, test, err):
        print("ERR!", test, err)

    # Polyfill.
    def addSkip(self, test, reason):
        print("SKIP!", test, reason)

    def addIgnore(self, test, reason):
        print("IGNORE!", test, reason)

    def onStart(self, test):
        print("ON_START!", test)

    def onEnd(self):
        print("ON_END!")

    def addOutputMismatch(self, test, ret, got, expected):
        return False

    def stopTest(self, test, interrupted=False):
        super(TestResult, self).stopTest(test)