Merge ~lloydwaltersj/maas:ui-theme-config into maas:master

[Jack Lloyd-Walters]

add UI theme configuration to MAAS

I believe this implements the UI config that was requested in #1979256

[MAAS Lander (maas-lander)]

UNIT TESTS
-b ui-theme-config lp:~lloydwaltersj/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 9e358e80a0e19d66af07ea0cbafd2f8cd9689ffa

review: Approve

[Adam Collard (adam-collard)]

Please add a test that theme is a valid config option and is str-like

[MAAS Lander (maas-lander)]

UNIT TESTS
-b ui-theme-config lp:~lloydwaltersj/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/13099/console
COMMIT: c8d0ad2008f58506d7e512b10e158d05936e8b4e

review: Needs Fixing

[MAAS Lander (maas-lander)]

UNIT TESTS
-b ui-theme-config lp:~lloydwaltersj/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 39075efc8e80e13df4deef2f4b8c257ed8b604da

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b ui-theme-config lp:~lloydwaltersj/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: d174627868d573a942f6d32412dfa6d445d79758

review: Approve

[Alberto Donato (ack)]

+1, nice

review: Approve

[MAAS Lander (maas-lander)]

UNABLE TO START LANDING

STATUS: MISSING COMMIT MESSAGE

diff --git a/src/maasserver/forms/__init__.py b/src/maasserver/forms/__init__.py
index 63e07cc..59b1b12 100644
--- a/src/maasserver/forms/__init__.py
+++ b/src/maasserver/forms/__init__.py
@@ -1706,6 +1706,7 @@ class MAASForm(ConfigForm):
     """Settings page, MAAS section."""
 
     maas_name = get_config_field("maas_name")
+    theme = get_config_field("theme")
     enable_analytics = get_config_field("enable_analytics")
 
 
diff --git a/src/maasserver/forms/settings.py b/src/maasserver/forms/settings.py
index d9e7d6e..f9887e1 100644
--- a/src/maasserver/forms/settings.py
+++ b/src/maasserver/forms/settings.py
@@ -287,6 +287,14 @@ CONFIG_ITEMS = {
         "form": forms.CharField,
         "form_kwargs": {"label": "MAAS name"},
     },
+    "theme": {
+        "default": "",
+        "form": forms.CharField,
+        "form_kwargs": {
+            "label": "MAAS theme",
+            "required": False,
+        },
+    },
     "kernel_opts": {
         "default": None,
         "form": forms.CharField,
diff --git a/src/maasserver/forms/tests/test_settings.py b/src/maasserver/forms/tests/test_settings.py
index f0cd075..010dbfb 100644
--- a/src/maasserver/forms/tests/test_settings.py
+++ b/src/maasserver/forms/tests/test_settings.py
@@ -107,3 +107,19 @@ class TestMAASSyslogPortConfigSettings(MAASServerTestCase):
     def test_doesnt_allow_port_5248(self):
         field = get_config_field("maas_syslog_port")
         self.assertRaises(ValidationError, field.clean, "5248")
+
+
+class TestMAASThemeConfigSettings(MAASServerTestCase):
+    def test_default_value(self):
+        form = get_config_form("theme")
+        self.assertEqual({"theme": ""}, form.initial)
+
+    def test_theme_config(self):
+        value = factory.make_hex_string(size=6)
+        field = get_config_field("theme")
+        self.assertEqual(value, field.clean(value))
+
+    def test_theme_string_like(self):
+        value = [1, 2, 3]
+        field = get_config_field("theme")
+        self.assertEqual(str(value), field.clean(value))
diff --git a/src/maasserver/models/config.py b/src/maasserver/models/config.py
index 0a90053..d1540d0 100644
--- a/src/maasserver/models/config.py
+++ b/src/maasserver/models/config.py
@@ -59,6 +59,7 @@ def get_default_config():
         # Network section configuration.
         "maas_url": "http://localhost:5240/MAAS",
         "maas_name": gethostname(),
+        "theme": "",
         "default_osystem": DEFAULT_OS.name,
         "default_distro_series": DEFAULT_OS.get_default_release(),
         # Proxy settings