diff --git a/coloredlogs/tests.py b/coloredlogs/tests.py
index 38f2d97..c4353f1 100644
--- a/coloredlogs/tests.py
+++ b/coloredlogs/tests.py
@@ -184,48 +184,6 @@ class ColoredLogsTestCase(TestCase):
             # Make sure colored logging is disabled.
             assert not isinstance(handler.formatter, ColoredFormatter)
 
-    def test_system_logging(self):
-        """Make sure the :class:`coloredlogs.syslog.SystemLogging` context manager works."""
-        system_log_file = self.find_system_log()
-        expected_message = random_string(50)
-        with SystemLogging(programname='coloredlogs-test-suite') as syslog:
-            if not syslog:
-                return self.skipTest("couldn't connect to syslog daemon")
-            # When I tried out the system logging support on macOS 10.13.1 on
-            # 2018-01-05 I found that while WARNING and ERROR messages show up
-            # in the system log DEBUG and INFO messages don't. This explains
-            # the importance of the level of the log message below.
-            logging.error("%s", expected_message)
-        # Retry the following assertion (for up to 60 seconds) to give the
-        # logging daemon time to write our log message to disk. This
-        # appears to be needed on MacOS workers on Travis CI, see:
-        # https://travis-ci.org/xolox/python-coloredlogs/jobs/325245853
-        retry(lambda: check_contents(system_log_file, expected_message, True))
-
-    def test_syslog_shortcut_simple(self):
-        """Make sure that ``coloredlogs.install(syslog=True)`` works."""
-        system_log_file = self.find_system_log()
-        expected_message = random_string(50)
-        with cleanup_handlers():
-            # See test_system_logging() for the importance of this log level.
-            coloredlogs.install(syslog=True)
-            logging.error("%s", expected_message)
-        # See the comments in test_system_logging() on why this is retried.
-        retry(lambda: check_contents(system_log_file, expected_message, True))
-
-    def test_syslog_shortcut_enhanced(self):
-        """Make sure that ``coloredlogs.install(syslog='warning')`` works."""
-        system_log_file = self.find_system_log()
-        the_expected_message = random_string(50)
-        not_an_expected_message = random_string(50)
-        with cleanup_handlers():
-            # See test_system_logging() for the importance of these log levels.
-            coloredlogs.install(syslog='error')
-            logging.warning("%s", not_an_expected_message)
-            logging.error("%s", the_expected_message)
-        # See the comments in test_system_logging() on why this is retried.
-        retry(lambda: check_contents(system_log_file, the_expected_message, True))
-        retry(lambda: check_contents(system_log_file, not_an_expected_message, False))
 
     def test_name_normalization(self):
         """Make sure :class:`~coloredlogs.NameNormalizer` works as intended."""
@@ -369,34 +327,6 @@ class ColoredLogsTestCase(TestCase):
         logging.info("This should be timestamped according to #45.")
         assert re.match(r'^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}\+\d{4}\s', stream.getvalue())
 
-    def test_plain_text_output_format(self):
-        """Inspect the plain text output of coloredlogs."""
-        logger = VerboseLogger(random_string(25))
-        stream = StringIO()
-        install(level=logging.NOTSET, logger=logger, stream=stream)
-        # Test that filtering on severity works.
-        logger.setLevel(logging.INFO)
-        logger.debug("No one should see this message.")
-        assert len(stream.getvalue().strip()) == 0
-        # Test that the default output format looks okay in plain text.
-        logger.setLevel(logging.NOTSET)
-        for method, severity in ((logger.debug, 'DEBUG'),
-                                 (logger.info, 'INFO'),
-                                 (logger.verbose, 'VERBOSE'),
-                                 (logger.warning, 'WARNING'),
-                                 (logger.error, 'ERROR'),
-                                 (logger.critical, 'CRITICAL')):
-            # Prepare the text.
-            text = "This is a message with severity %r." % severity.lower()
-            # Log the message with the given severity.
-            method(text)
-            # Get the line of output generated by the handler.
-            output = stream.getvalue()
-            lines = output.splitlines()
-            last_line = lines[-1]
-            assert text in last_line
-            assert severity in last_line
-            assert PLAIN_TEXT_PATTERN.match(last_line)
 
     def test_html_conversion(self):
         """Check the conversion from ANSI escape sequences to HTML."""
@@ -503,12 +433,6 @@ class ColoredLogsTestCase(TestCase):
         for name in 'debug', 'info', 'warning', 'error', 'critical':
             assert name.upper() in output
 
-    def test_cli_conversion(self):
-        """Test the command line HTML conversion."""
-        output = main('coloredlogs', '--convert', 'coloredlogs', '--demo', capture=True)
-        # Make sure the output is encoded as HTML.
-        assert '<span' in output
-
     def test_empty_conversion(self):
         """
         Test that conversion of empty output produces no HTML.