Add type validation.

Argparse driven argument type validation is added for the
`--junit-xml` and `--confcutdir` arguments.

The commit partially reverts #2080. Closes #2089.

Author: decentral1se

_pytest/config.py

@@ -70,6 +70,18 @@ class UsageError(Exception):
     """ error in pytest usage or invocation"""
 
 
+def filename(path):
+    """Argparse type validator for filename arguments"""
+    if os.path.isdir(path):
+        raise UsageError("Must be a filename, given: {0}".format(path))
+    return path
+
+def directory(path):
+    """Argparse type validator for directory arguments"""
+    if not os.path.isdir(path):
+        raise UsageError("Must be a directory, given: {0}".format(path))
+    return path
+
 _preinit = []
 
 default_plugins = (
@@ -996,7 +1008,6 @@ def _warn_about_missing_assertion(self, mode):
                                  "(are you using python -O?)\n")
 
     def _preparse(self, args, addopts=True):
-        import pytest
         self._initini(args)
         if addopts:
             args[:] = shlex.split(os.environ.get('PYTEST_ADDOPTS', '')) + args
@@ -1009,9 +1020,7 @@ def _preparse(self, args, addopts=True):
         self.pluginmanager.consider_env()
         self.known_args_namespace = ns = self._parser.parse_known_args(args, namespace=self.option.copy())
         confcutdir = self.known_args_namespace.confcutdir
-        if confcutdir and not os.path.isdir(confcutdir):
-            raise pytest.UsageError('--confcutdir must be a directory, given: {0}'.format(confcutdir))
-        if confcutdir is None and self.inifile:
+        if self.known_args_namespace.confcutdir is None and self.inifile:
             confcutdir = py.path.local(self.inifile).dirname
             self.known_args_namespace.confcutdir = confcutdir
         try:

_pytest/junitxml.py

@@ -14,6 +14,7 @@
 import sys
 import time
 import pytest
+from _pytest.config import filename
 
 # Python 2.X and 3.X compatibility
 if sys.version_info[0] < 3:
@@ -214,6 +215,7 @@ def pytest_addoption(parser):
         action="store",
         dest="xmlpath",
         metavar="path",
+        type=filename,
         default=None,
         help="create junit-xml style report file at given path.")
     group.addoption(

_pytest/main.py

@@ -11,6 +11,7 @@
 except ImportError:
     from UserDict import DictMixin as MappingMixin
 
+from _pytest.config import directory
 from _pytest.runner import collect_one_node
 
 tracebackcutdir = py.path.local(_pytest.__file__).dirpath()
@@ -58,7 +59,7 @@ def pytest_addoption(parser):
     # when changing this to --conf-cut-dir, config.py Conftest.setinitial
     # needs upgrading as well
     group.addoption('--confcutdir', dest="confcutdir", default=None,
-        metavar="dir",
+        metavar="dir", type=directory,
         help="only load conftest.py's relative to specified dir.")
     group.addoption('--noconftest', action="store_true",
         dest="noconftest", default=False,

testing/test_junitxml.py

@@ -715,6 +715,10 @@ def test_pass():
     assert result.ret == 0
     assert testdir.tmpdir.join("path/to/results.xml").check()
 
+def test_logxml_check_isdir(testdir):
+    """Give an error if --junit-xml is a directory (#2089)"""
+    result = testdir.runpytest("--junit-xml=.")
+    result.stderr.fnmatch_lines(["*Must be a filename*"])
 
 def test_escaped_parametrized_names_xml(testdir):
     testdir.makepyfile("""