handle 405s

Handle werkzeug http errors separately. Also, improve the generic
`Exception` handler to be more flexible when exceptions don't look
like http errors.

note: because they're 405s the route isn't matched, so the v2 error
handlers don't trip properly. this might be an issue because the
internal endpoints expect a different return format. Might have to
think about how to handle this.

tests/app/v2/test_errors.py

@@ -1,4 +1,3 @@
-import json
 import pytest
 from flask import url_for
 from sqlalchemy.exc import DataError
@@ -10,9 +9,13 @@ def app_for_test(mocker):
     from flask import Blueprint
     from app.authentication.auth import AuthError
     from app.v2.errors import BadRequestError, TooManyRequestsError, JobIncompleteError
+    from app import init_app
 
     app = flask.Flask(__name__)
     app.config['TESTING'] = True
+    init_app(app)
+    from app import statsd_client
+    statsd_client.init_app(app)
 
     from app.v2.errors import register_errors
     blue = Blueprint("v2_under_test", __name__, url_prefix='/v2/under_test')
@@ -58,7 +61,7 @@ def test_auth_error(app_for_test):
         with app_for_test.test_client() as client:
             response = client.get(url_for('v2_under_test.raising_auth_error'))
             assert response.status_code == 403
-            error = json.loads(response.get_data(as_text=True))
+            error = response.json
             assert error == {"status_code": 403,
                              "errors": [{"error": "AuthError",
                                          "message": "some message"}]}
@@ -69,7 +72,7 @@ def test_bad_request_error(app_for_test):
         with app_for_test.test_client() as client:
             response = client.get(url_for('v2_under_test.raising_bad_request'))
             assert response.status_code == 400
-            error = json.loads(response.get_data(as_text=True))
+            error = response.json
             assert error == {"status_code": 400,
                              "errors": [{"error": "BadRequestError",
                                          "message": "you forgot the thing"}]}
@@ -80,7 +83,7 @@ def test_too_many_requests_error(app_for_test):
         with app_for_test.test_client() as client:
             response = client.get(url_for('v2_under_test.raising_too_many_requests'))
             assert response.status_code == 429
-            error = json.loads(response.get_data(as_text=True))
+            error = response.json
             assert error == {"status_code": 429,
                              "errors": [{"error": "TooManyRequestsError",
                                          "message": "Exceeded send limits (452) for today"}]}
@@ -91,7 +94,7 @@ def test_validation_error(app_for_test):
         with app_for_test.test_client() as client:
             response = client.get(url_for('v2_under_test.raising_validation_error'))
             assert response.status_code == 400
-            error = json.loads(response.get_data(as_text=True))
+            error = response.json
             assert len(error.keys()) == 2
             assert error['status_code'] == 400
             assert len(error['errors']) == 2
@@ -106,7 +109,7 @@ def test_data_errors(app_for_test):
         with app_for_test.test_client() as client:
             response = client.get(url_for('v2_under_test.raising_data_error'))
             assert response.status_code == 404
-            error = json.loads(response.get_data(as_text=True))
+            error = response.json
             assert error == {"status_code": 404,
                              "errors": [{"error": "DataError", "message": "No result found"}]}
 
@@ -116,7 +119,7 @@ def test_job_incomplete_errors(app_for_test):
         with app_for_test.test_client() as client:
             response = client.get(url_for('v2_under_test.raising_job_incomplete_error'))
             assert response.status_code == 500
-            error = json.loads(response.get_data(as_text=True))
+            error = response.json
             assert error == {"status_code": 500,
                              "errors": [{"error": "JobIncompleteError", "message": "Raising job incomplete error"}]}
 
@@ -126,6 +129,19 @@ def test_internal_server_error_handler(app_for_test):
         with app_for_test.test_client() as client:
             response = client.get(url_for("v2_under_test.raising_exception"))
             assert response.status_code == 500
-            error = json.loads(response.get_data(as_text=True))
+            error = response.json
             assert error == {"status_code": 500,
                              "errors": [{"error": "AssertionError", "message": "Internal server error"}]}
+
+
+def test_bad_method(app_for_test):
+    with app_for_test.test_request_context():
+        with app_for_test.test_client() as client:
+            response = client.post(url_for("v2_under_test.raising_exception"))
+
+            assert response.status_code == 405
+
+            assert response.json == {
+                "result": "error",
+                "message": "The method is not allowed for the requested URL."
+            }