diff --git a/.travis.yml b/.travis.yml
index 1551f17ec5..2a60d20c6f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,6 +15,9 @@ services:
   - mysql
 
 install:
+  - pip install flake8  # pytest
+  # stop the build if there are Python syntax errors or undefined names
+  - flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics
   - sudo rm /etc/apt/sources.list.d/docker.list
   - sudo apt-get purge -y mysql-common mysql-server mysql-client
   - nvm install v7.10.0
diff --git a/frappe/core/doctype/doctype/boilerplate/controller.py b/frappe/core/doctype/doctype/boilerplate/controller._py
similarity index 100%
rename from frappe/core/doctype/doctype/boilerplate/controller.py
rename to frappe/core/doctype/doctype/boilerplate/controller._py
diff --git a/frappe/core/doctype/doctype/boilerplate/test_controller.py b/frappe/core/doctype/doctype/boilerplate/test_controller._py
similarity index 100%
rename from frappe/core/doctype/doctype/boilerplate/test_controller.py
rename to frappe/core/doctype/doctype/boilerplate/test_controller._py
diff --git a/frappe/core/doctype/doctype/doctype.py b/frappe/core/doctype/doctype/doctype.py
index 2e13e64f57..40207a24dd 100644
--- a/frappe/core/doctype/doctype/doctype.py
+++ b/frappe/core/doctype/doctype/doctype.py
@@ -330,10 +330,10 @@ class DocType(Document):
 
 	def make_controller_template(self):
 		"""Make boilerplate controller template."""
-		make_boilerplate("controller.py", self)
+		make_boilerplate("controller._py", self)
 
 		if not (self.istable or self.issingle):
-			make_boilerplate("test_controller.py", self.as_dict())
+			make_boilerplate("test_controller._py", self.as_dict())
 
 		if not self.istable:
 			make_boilerplate("controller.js", self.as_dict())
diff --git a/frappe/core/doctype/domain/domain.json b/frappe/core/doctype/domain/domain.json
index 35b68d0714..f257d02ae8 100644
--- a/frappe/core/doctype/domain/domain.json
+++ b/frappe/core/doctype/domain/domain.json
@@ -26,7 +26,7 @@
    "ignore_xss_filter": 0, 
    "in_filter": 0, 
    "in_global_search": 0, 
-   "in_list_view": 0, 
+   "in_list_view": 1, 
    "in_standard_filter": 0, 
    "label": "Domain", 
    "length": 0, 
@@ -54,7 +54,7 @@
  "issingle": 0, 
  "istable": 0, 
  "max_attachments": 0, 
- "modified": "2017-06-16 13:03:25.430679", 
+ "modified": "2017-07-26 21:29:00.353105", 
  "modified_by": "Administrator", 
  "module": "Core", 
  "name": "Domain", 
diff --git a/frappe/core/doctype/domain/test_domain.js b/frappe/core/doctype/domain/test_domain.js
new file mode 100644
index 0000000000..6d8bd8039d
--- /dev/null
+++ b/frappe/core/doctype/domain/test_domain.js
@@ -0,0 +1,23 @@
+/* eslint-disable */
+// rename this file from _test_[name] to test_[name] to activate
+// and remove above this line
+
+QUnit.test("test: Domain", function (assert) {
+	let done = assert.async();
+
+	// number of asserts
+	assert.expect(1);
+
+	frappe.run_serially('Domain', [
+		// insert a new Domain
+		() => frappe.tests.make([
+			// values to be set
+			{key: 'value'}
+		]),
+		() => {
+			assert.equal(cur_frm.doc.key, 'value');
+		},
+		() => done()
+	]);
+
+});
diff --git a/frappe/core/doctype/has_role/has_role.py b/frappe/core/doctype/has_role/has_role.py
index 44c27098d9..45e76c85a1 100644
--- a/frappe/core/doctype/has_role/has_role.py
+++ b/frappe/core/doctype/has_role/has_role.py
@@ -7,7 +7,6 @@ import frappe
 from frappe.model.document import Document
 
 class HasRole(Document):
-	def validate(self):
-		if cint(self.get("__islocal")) and frappe.db.exists("Has Role", {
-				"parent": self.parent, "role": self.role}):
+	def before_insert(self):
+		if frappe.db.exists("Has Role", {"parent": self.parent, "role": self.role}):
 			frappe.throw(frappe._("User '{0}' already has the role '{1}'").format(self.parent, self.role))
diff --git a/frappe/email/doctype/newsletter/newsletter.py b/frappe/email/doctype/newsletter/newsletter.py
index 29ecbee853..4f4713edbe 100755
--- a/frappe/email/doctype/newsletter/newsletter.py
+++ b/frappe/email/doctype/newsletter/newsletter.py
@@ -13,7 +13,6 @@ from frappe.utils.background_jobs import enqueue
 from frappe.utils.scheduler import log
 from frappe.email.queue import send
 from frappe.email.doctype.email_group.email_group import add_subscribers
-from frappe.utils.file_manager import get_file
 from frappe.utils import parse_addr
 
 
@@ -68,7 +67,7 @@ class Newsletter(Document):
 			files = frappe.get_all("File", fields = ["name"], filters = {"attached_to_doctype": "Newsletter",
 				"attached_to_name":self.name}, order_by="creation desc")
 
-			for file in files:
+			for a in files:
 				try:
 					# these attachments will be attached on-demand
 					# and won't be stored in the message
diff --git a/frappe/integrations/doctype/gsuite_settings/gsuite_settings.py b/frappe/integrations/doctype/gsuite_settings/gsuite_settings.py
index 9b6be3422d..29b1b64897 100644
--- a/frappe/integrations/doctype/gsuite_settings/gsuite_settings.py
+++ b/frappe/integrations/doctype/gsuite_settings/gsuite_settings.py
@@ -17,7 +17,7 @@ class GSuiteSettings(Document):
 
 	def get_access_token(self):
 		if not self.refresh_token:
-			raise UserError(_("Google GSuite is not configured."))
+			raise frappe.ValidationError(_("Google GSuite is not configured."))
 		data = {
 			'client_id': self.client_id,
 			'client_secret': self.get_password(fieldname='client_secret',raise_exception=False),
diff --git a/frappe/modules/utils.py b/frappe/modules/utils.py
index 2acb5b5db6..20ff7bb28f 100644
--- a/frappe/modules/utils.py
+++ b/frappe/modules/utils.py
@@ -206,6 +206,8 @@ def get_app_publisher(module):
 def make_boilerplate(template, doc, opts=None):
 	target_path = get_doc_path(doc.module, doc.doctype, doc.name)
 	template_name = template.replace("controller", scrub(doc.name))
+	if template_name.endswith('._py'):
+		template_name = template_name[:-4] + '.py'
 	target_file_path = os.path.join(target_path, template_name)
 
 	if not doc: doc = {}