Rework things a bit, remove py.test, allow multiple instances, and a validator.cli

4 files changed, 312 insertions, 96 deletions

diff --git a/jsonschema/_reflect.py b/jsonschema/_reflect.py
new file mode 100644
index 0000000..d09e38f
--- /dev/null
+++ b/jsonschema/_reflect.py
@@ -0,0 +1,155 @@
+# -*- test-case-name: twisted.test.test_reflect -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Standardized versions of various cool and/or strange things that you can do
+with Python's reflection capabilities.
+"""
+
+import sys
+
+from jsonschema.compat import PY3
+
+
+class _NoModuleFound(Exception):
+    """
+    No module was found because none exists.
+    """
+
+
+
+class InvalidName(ValueError):
+    """
+    The given name is not a dot-separated list of Python objects.
+    """
+
+
+
+class ModuleNotFound(InvalidName):
+    """
+    The module associated with the given name doesn't exist and it can't be
+    imported.
+    """
+
+
+
+class ObjectNotFound(InvalidName):
+    """
+    The object associated with the given name doesn't exist and it can't be
+    imported.
+    """
+
+
+
+if PY3:
+    def reraise(exception, traceback):
+        raise exception.with_traceback(traceback)
+else:
+    exec("""def reraise(exception, traceback):
+        raise exception.__class__, exception, traceback""")
+
+reraise.__doc__ = """
+Re-raise an exception, with an optional traceback, in a way that is compatible
+with both Python 2 and Python 3.
+
+Note that on Python 3, re-raised exceptions will be mutated, with their
+C{__traceback__} attribute being set.
+
+@param exception: The exception instance.
+@param traceback: The traceback to use, or C{None} indicating a new traceback.
+"""
+
+
+def _importAndCheckStack(importName):
+    """
+    Import the given name as a module, then walk the stack to determine whether
+    the failure was the module not existing, or some code in the module (for
+    example a dependent import) failing.  This can be helpful to determine
+    whether any actual application code was run.  For example, to distiguish
+    administrative error (entering the wrong module name), from programmer
+    error (writing buggy code in a module that fails to import).
+
+    @param importName: The name of the module to import.
+    @type importName: C{str}
+    @raise Exception: if something bad happens.  This can be any type of
+        exception, since nobody knows what loading some arbitrary code might
+        do.
+    @raise _NoModuleFound: if no module was found.
+    """
+    try:
+        return __import__(importName)
+    except ImportError:
+        excType, excValue, excTraceback = sys.exc_info()
+        while excTraceback:
+            execName = excTraceback.tb_frame.f_globals["__name__"]
+            # in Python 2 execName is None when an ImportError is encountered,
+            # where in Python 3 execName is equal to the importName.
+            if execName is None or execName == importName:
+                reraise(excValue, excTraceback)
+            excTraceback = excTraceback.tb_next
+        raise _NoModuleFound()
+
+
+
+def namedAny(name):
+    """
+    Retrieve a Python object by its fully qualified name from the global Python
+    module namespace.  The first part of the name, that describes a module,
+    will be discovered and imported.  Each subsequent part of the name is
+    treated as the name of an attribute of the object specified by all of the
+    name which came before it.  For example, the fully-qualified name of this
+    object is 'twisted.python.reflect.namedAny'.
+
+    @type name: L{str}
+    @param name: The name of the object to return.
+
+    @raise InvalidName: If the name is an empty string, starts or ends with
+        a '.', or is otherwise syntactically incorrect.
+
+    @raise ModuleNotFound: If the name is syntactically correct but the
+        module it specifies cannot be imported because it does not appear to
+        exist.
+
+    @raise ObjectNotFound: If the name is syntactically correct, includes at
+        least one '.', but the module it specifies cannot be imported because
+        it does not appear to exist.
+
+    @raise AttributeError: If an attribute of an object along the way cannot be
+        accessed, or a module along the way is not found.
+
+    @return: the Python object identified by 'name'.
+    """
+    if not name:
+        raise InvalidName('Empty module name')
+
+    names = name.split('.')
+
+    # if the name starts or ends with a '.' or contains '..', the __import__
+    # will raise an 'Empty module name' error. This will provide a better error
+    # message.
+    if '' in names:
+        raise InvalidName(
+            "name must be a string giving a '.'-separated list of Python "
+            "identifiers, not %r" % (name,))
+
+    topLevelPackage = None
+    moduleNames = names[:]
+    while not topLevelPackage:
+        if moduleNames:
+            trialname = '.'.join(moduleNames)
+            try:
+                topLevelPackage = _importAndCheckStack(trialname)
+            except _NoModuleFound:
+                moduleNames.pop()
+        else:
+            if len(names) == 1:
+                raise ModuleNotFound("No module named %r" % (name,))
+            else:
+                raise ObjectNotFound('%r does not name an object' % (name,))
+
+    obj = topLevelPackage
+    for n in names[1:]:
+        obj = getattr(obj, n)
+
+    return obj
diff --git a/jsonschema/cli.py b/jsonschema/cli.py
index 69ac5af..bdde379 100644
--- a/jsonschema/cli.py
+++ b/jsonschema/cli.py
@@ -1,40 +1,72 @@
+from __future__ import absolute_import
 import argparse
 import json
 import sys
 
-from . import (
-    validate, Draft4Validator, Draft3Validator,
-    draft3_format_checker, draft4_format_checker,
+from jsonschema._reflect import namedAny
+from jsonschema.validators import validator_for
+
+
+def _namedAnyWithDefault(name):
+    if "." not in name:
+        name = "jsonschema." + name
+    return namedAny(name)
+
+
+def _json_file(path):
+    with open(path) as file:
+        return json.load(file)
+
+
+parser = argparse.ArgumentParser(
+    description="JSON Schema Validation CLI",
+)
+parser.add_argument(
+    "-i", "--instance",
+    action="append",
+    dest="instances",
+    type=_json_file,
+    help="a path to a JSON instance to validate "
+         "(may be specified multiple times)",
 )
-from .validators import validator_for
+parser.add_argument(
+    "-F", "--error-format",
+    default="{error.instance}: {error.message}\n",
+    help="the format to use for each error output message, specified in "
+         "a form suitable for passing to str.format, which will be called "
+         "with 'error' for each error",
+)
+parser.add_argument(
+    "-V", "--validator",
+    type=_namedAnyWithDefault,
+    help="the fully qualified object name of a validator to use, or, for "
+          "validators that are registered with jsonschema, simply the name "
+          "of the class.",
+)
+parser.add_argument(
+    "schema",
+    help="the JSON Schema to validate with",
+    type=_json_file,
+)
+
+
+def parse_args(args):
+    arguments = vars(parser.parse_args(args=args or ["--help"]))
+    if arguments["validator"] is None:
+        arguments["validator"] = validator_for(arguments["schema"])
+    return arguments
 
 
 def main(args=sys.argv[1:]):
-    parser = argparse.ArgumentParser(description='JSON Schema validator')
-    parser.add_argument('schema', help='filename of the JSON Schema')
-    parser.add_argument('document', help='filename of the JSON document to validate')
-    parser.add_argument('--format', help='validate value format', action='store_true')
-    args = parser.parse_args(args)
-
-    schema = json.load(open(args.schema, 'r'))
-    document = json.load(open(args.document, 'r'))
-
-    validator = validator_for(schema)
-    if args.format:
-        if validator == Draft4Validator:
-            format_checker = draft4_format_checker
-        elif validator == Draft3Validator:
-            format_checker = draft3_format_checker
-        else:
-            raise NotImplementedError("No format validator for %s specified"
-                                      % validator.__name__)
-    else:
-        format_checker = None
-
-    validate(document, schema, validator, format_checker=format_checker)
-    # validate raises if the document is invalid, and will show a Traceback to
-    # the user. If the document is valid, show a congratulating message.
-    print("JSON document is valid.")
-
-if __name__ == '__main__':
-    main()
+    sys.exit(run(arguments=parse_args(args=args)))
+
+
+def run(arguments, stdout=sys.stdout, stderr=sys.stderr):
+    error_format = arguments["error_format"]
+    validator = arguments["validator"](schema=arguments["schema"])
+    errored = False
+    for instance in arguments["instances"] or ():
+        for error in validator.iter_errors(instance):
+            stderr.write(error_format.format(error=error))
+            errored = True
+    return errored
diff --git a/jsonschema/compat.py b/jsonschema/compat.py
index e5394f0..6ca49ab 100644
--- a/jsonschema/compat.py
+++ b/jsonschema/compat.py
@@ -11,6 +11,7 @@ PY3 = sys.version_info[0] >= 3
 
 if PY3:
     zip = zip
+    from io import StringIO
     from urllib.parse import (
         unquote, urljoin, urlunsplit, SplitResult, urlsplit as _urlsplit
     )
@@ -20,6 +21,7 @@ if PY3:
     iteritems = operator.methodcaller("items")
 else:
     from itertools import izip as zip  # noqa
+    from StringIO import StringIO
     from urlparse import (
         urljoin, urlunsplit, SplitResult, urlsplit as _urlsplit # noqa
     )
diff --git a/jsonschema/tests/test_cli.py b/jsonschema/tests/test_cli.py
index ae930c4..3f43ded 100644
--- a/jsonschema/tests/test_cli.py
+++ b/jsonschema/tests/test_cli.py
@@ -1,78 +1,105 @@
-import StringIO
+from jsonschema import Draft4Validator, ValidationError, cli
+from jsonschema.compat import StringIO
+from jsonschema.tests.compat import mock, unittest
 
-import pytest
 
-from .compat import mock, unittest
-from .. import (
-    cli, Draft4Validator, Draft3Validator,
-    draft3_format_checker, draft4_format_checker,
-)
+def fake_validator(*errors):
+    errors = list(reversed(errors))
 
-MOCK_SCHEMAS = {
-    'draft3': {"$schema": "http://json-schema.org/draft-03/schema#"},
-    'draft4': {"$schema": "http://json-schema.org/draft-04/schema#"},
-}
+    class FakeValidator(object):
+        def __init__(self, *args, **kwargs):
+            pass
 
+        def iter_errors(self, instance):
+            if errors:
+                return errors.pop()
+            return []
+    return FakeValidator
 
-class TestCLI(unittest.TestCase):
-    def test_missing_arguments(self):
-        with pytest.raises(SystemExit) as e:
-            cli.main([])
 
-    @mock.patch('__builtin__.open')
-    @mock.patch('jsonschema.cli.validate')
-    def test_filename_argument_order(self, validate, open_):
-        def mock_file(filename, mode):
-            return StringIO.StringIO('{"filename": "%s"}' % filename)
-        open_.side_effect = mock_file
+class TestParser(unittest.TestCase):
 
-        cli.main(['document.json', 'schema.json'])
+    FakeValidator = fake_validator()
 
-        open_.assert_has_calls([mock.call('document.json', 'r'),
-                                mock.call('schema.json', 'r')],
-                               any_order=True)
-        self.assertEqual(open_.call_count, 2)
+    def setUp(self):
+        self.open = mock.mock_open(read_data='{}')
+        patch = mock.patch.object(cli, "open", self.open, create=True)
+        patch.start()
+        self.addCleanup(patch.stop)
 
-        validate.assert_called_once_with({'filename': 'schema.json'},
-                                         {'filename': 'document.json'},
-                                         Draft4Validator,
-                                         format_checker=None)
+    def test_find_validator_by_fully_qualified_object_name(self):
+        arguments = cli.parse_args(
+            [
+                "--validator",
+                "jsonschema.tests.test_cli.TestParser.FakeValidator",
+                "--instance", "foo.json",
+                "schema.json",
+            ]
+        )
+        self.assertIs(arguments["validator"], self.FakeValidator)
 
-    @mock.patch('__builtin__.open')
-    @mock.patch('jsonschema.cli.json.load')
-    @mock.patch('jsonschema.cli.validate')
-    def test_raise_exception(self, validate, json_load, open_):
-        validate.side_effect = Exception('Did not validate correctly')
-        with pytest.raises(Exception) as e:
-            cli.main([None, None])
-        self.assertEqual(e.exconly(), "Exception: Did not validate correctly")
+    def test_find_validator_in_jsonschema(self):
+        arguments = cli.parse_args(
+            [
+                "--validator", "Draft4Validator",
+                "--instance", "foo.json",
+                "schema.json",
+            ]
+        )
+        self.assertIs(arguments["validator"], Draft4Validator)
 
-    @mock.patch('__builtin__.open')
-    @mock.patch('jsonschema.cli.json.load')
-    @mock.patch('jsonschema.cli.validate')
-    def test_format(self, validate, json_load, open_):
-        schema = {"$schema": "http://json-schema.org/draft-04/schema#"}
-        json_load.return_value = schema
 
-        cli.main([None, None])
-        validate.assert_called_once_with(schema, schema, Draft4Validator,
-                                         format_checker=None)
-        validate.reset_mock()
-        cli.main([None, None, '--format'])
-        validate.assert_called_once_with(schema, schema, Draft4Validator,
-                                         format_checker=draft4_format_checker)
+class TestCLI(unittest.TestCase):
+    def test_successful_validation(self):
+        stdout, stderr = StringIO(), StringIO()
+        exit_code = cli.run(
+            {
+                "validator" : fake_validator(),
+                "schema" : {},
+                "instances" : [1],
+                "error_format" : "{error.message}",
+            },
+            stdout=stdout,
+            stderr=stderr,
+        )
+        self.assertFalse(stdout.getvalue())
+        self.assertFalse(stderr.getvalue())
+        self.assertEqual(exit_code, 0)
 
-    @mock.patch('__builtin__.open')
-    @mock.patch('jsonschema.cli.json.load')
-    @mock.patch('jsonschema.cli.validate')
-    def test_draft3(self, validate, json_load, open_):
-        schema = {"$schema": "http://json-schema.org/draft-03/schema#"}
-        json_load.return_value = schema
+    def test_unsuccessful_validation(self):
+        error = ValidationError("I am an error!", instance=1)
+        stdout, stderr = StringIO(), StringIO()
+        exit_code = cli.run(
+            {
+                "validator" : fake_validator([error]),
+                "schema" : {},
+                "instances" : [1],
+                "error_format" : "{error.instance} - {error.message}",
+            },
+            stdout=stdout,
+            stderr=stderr,
+        )
+        self.assertFalse(stdout.getvalue())
+        self.assertEqual(stderr.getvalue(), "1 - I am an error!")
+        self.assertEqual(exit_code, 1)
 
-        cli.main([None, None])
-        validate.assert_called_once_with(schema, schema, Draft3Validator,
-                                         format_checker=None)
-        validate.reset_mock()
-        cli.main([None, None, '--format'])
-        validate.assert_called_once_with(schema, schema, Draft3Validator,
-                                         format_checker=draft3_format_checker)
+    def test_unsuccessful_validation_multiple_instances(self):
+        first_errors = [
+            ValidationError("9", instance=1),
+            ValidationError("8", instance=1),
+        ]
+        second_errors = [ValidationError("7", instance=2)]
+        stdout, stderr = StringIO(), StringIO()
+        exit_code = cli.run(
+            {
+                "validator" : fake_validator(first_errors, second_errors),
+                "schema" : {},
+                "instances" : [1, 2],
+                "error_format" : "{error.instance} - {error.message}\t",
+            },
+            stdout=stdout,
+            stderr=stderr,
+        )
+        self.assertFalse(stdout.getvalue())
+        self.assertEqual(stderr.getvalue(), "1 - 9\t1 - 8\t2 - 7\t")
+        self.assertEqual(exit_code, 1)