config: Start adding basic validators + tests for new config values.

mopidy/utils/config.py

@@ -0,0 +1,19 @@
+from __future__ import unicode_literals
+
+
+def validate_choice(value, choices):
+    """Choice validation, normally called in config value's validate()."""
+    if choices is not None and value not in choices :
+        raise ValueError('must be one of %s.' % ', '.join(choices))
+
+
+def validate_minimum(value, minimum):
+    """Minimum validation, normally called in config value's validate()."""
+    if minimum is not None and value < minimum:
+        raise ValueError('must be larger than %s.' % minimum)
+
+
+def validate_maximum(value, maximum):
+    """Maximum validation, normally called in config value's validate()."""
+    if maximum is not None and value > maximum:
+        raise ValueError('must be smaller than %s.' % maximum)

tests/utils/config_test.py

@@ -0,0 +1,53 @@
+from __future__ import unicode_literals
+
+from mopidy.utils import config
+
+from tests import unittest
+
+
+class ValidateChoiceTest(unittest.TestCase):
+    def test_no_choices_passes(self):
+        config.validate_choice('foo', None)
+
+    def test_valid_value_passes(self):
+        config.validate_choice('foo', ['foo', 'bar', 'baz'])
+
+    def test_empty_choices_fails(self):
+        with self.assertRaises(ValueError):
+            config.validate_choice('foo', [])
+
+    def test_invalid_value_fails(self):
+        with self.assertRaises(ValueError):
+            config.validate_choice('foobar', ['foo', 'bar', 'baz'])
+
+
+class ValidateMinimumTest(unittest.TestCase):
+    def test_no_minimum_passes(self):
+        config.validate_minimum(10, None)
+
+    def test_valid_value_passes(self):
+        config.validate_minimum(10, 5)
+
+    def test_to_small_value_fails(self):
+        with self.assertRaises(ValueError):
+            config.validate_minimum(10, 20)
+
+    def test_to_small_value_fails_with_zero_as_minimum(self):
+        with self.assertRaises(ValueError):
+            config.validate_minimum(-1, 0)
+
+
+class ValidateMaximumTest(unittest.TestCase):
+    def test_no_maximum_passes(self):
+        config.validate_maximum(5, None)
+
+    def test_valid_value_passes(self):
+        config.validate_maximum(5, 10)
+
+    def test_to_large_value_fails(self):
+        with self.assertRaises(ValueError):
+            config.validate_maximum(10, 5)
+
+    def test_to_large_value_fails_with_zero_as_maximum(self):
+        with self.assertRaises(ValueError):
+            config.validate_maximum(5, 0)