From beb8f8bc4eba0aec6d11ccdfdce6142fe03d3932 Mon Sep 17 00:00:00 2001
From: Matt Westcott <matt@west.co.tt>
Date: Tue, 15 Dec 2015 18:44:09 +0000
Subject: [PATCH] Add system check to confirm that compiled CSS files are
 present.

Fixes #1720. Thanks to Shu Ishida for initial development on this feature.
---
 wagtail/wagtailadmin/apps.py   |  2 ++
 wagtail/wagtailadmin/checks.py | 30 ++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 wagtail/wagtailadmin/checks.py

diff --git a/wagtail/wagtailadmin/apps.py b/wagtail/wagtailadmin/apps.py
index c963dadef..7130ba77f 100644
--- a/wagtail/wagtailadmin/apps.py
+++ b/wagtail/wagtailadmin/apps.py
@@ -1,5 +1,7 @@
 from django.apps import AppConfig
 
+from . import checks  # NOQA
+
 
 class WagtailAdminAppConfig(AppConfig):
     name = 'wagtail.wagtailadmin'
diff --git a/wagtail/wagtailadmin/checks.py b/wagtail/wagtailadmin/checks.py
new file mode 100644
index 000000000..81b47d564
--- /dev/null
+++ b/wagtail/wagtailadmin/checks.py
@@ -0,0 +1,30 @@
+import os
+
+from django.core.checks import Error, register
+
+
+@register()
+def css_install_check(app_configs, **kwargs):
+    errors = []
+
+    css_path = os.path.join(
+        os.path.dirname(__file__), 'static', 'wagtailadmin', 'css', 'normalize.css'
+    )
+
+    if not os.path.isfile(css_path):
+        error_hint = """
+            Most likely you are running a development (non-packaged) copy of
+            Wagtail and have not built the static assets -
+            see http://docs.wagtail.io/en/latest/contributing/developing.html
+
+            File not found: %s
+        """ % css_path
+
+        errors.append(
+            Error(
+                "CSS for the Wagtail admin is missing",
+                hint=error_hint,
+                id='wagtailadmin.E001',
+            )
+        )
+    return errors