Added config validator and tests for it

tests/clientlib/validate_config_test.py

@@ -0,0 +1,61 @@
+
+import jsonschema
+import jsonschema.exceptions
+import pytest
+
+from pre_commit.clientlib.validate_config import CONFIG_JSON_SCHEMA
+from pre_commit.clientlib.validate_config import run
+
+
+def test_returns_0_for_valid_config():
+    assert run(['example_pre-commit-config.yaml']) == 0
+
+
+def test_returns_0_for_out_manifest():
+    assert run([]) == 0
+
+
+def test_returns_1_for_failing():
+    assert run(['tests/data/valid_yaml_but_invalid_config.yaml']) == 1
+
+def is_valid_according_to_schema(obj, schema):
+    try:
+        jsonschema.validate(obj, schema)
+        return True
+    except jsonschema.exceptions.ValidationError:
+        return False
+
+
+@pytest.mark.parametrize(('manifest_obj', 'expected'), (
+    ([], False),
+    (
+        [{
+          'repo': 'git@github.com:pre-commit/pre-commit-hooks',
+          'sha': 'cd74dc150c142c3be70b24eaf0b02cae9d235f37',
+          'hooks': [
+              {
+                  'id': 'pyflakes',
+                  'files': '*.py',
+              }
+          ]
+        }],
+        True,
+    ),
+    (
+        [{
+          'repo': 'git@github.com:pre-commit/pre-commit-hooks',
+          'sha': 'cd74dc150c142c3be70b24eaf0b02cae9d235f37',
+          'hooks': [
+              {
+                  'id': 'pyflakes',
+                  'files': '*.py',
+                  'args': ['foo', 'bar', 'baz'],
+              }
+          ]
+        }],
+        True,
+    ),
+))
+def test_is_valid_according_to_schema(manifest_obj, expected):
+    ret = is_valid_according_to_schema(manifest_obj, CONFIG_JSON_SCHEMA)
+    assert ret is expected

tests/data/valid_yaml_but_invalid_config.yaml

@@ -0,0 +1,11 @@
+
+-
+    repo: git@github.com:pre-commit/pre-commit-hooks
+    hooks:
+        -
+            id: pyflakes
+        -
+            id: jslint
+        -
+            id: trim_trailing_whitespace
+            files: '*.py'