Add some very basic tests

tests/test_basic.py

@@ -1,11 +1,44 @@
+import pytest
+
 from llconfig import Config
 
 
 def test_basic():
-    c = Config(env_prefix='VIRTUAL_')
+    c = Config()
     c.init('HOST', str, '0.0.0.0')
     c.init('PORT', int, 8080)
     c.load()
 
     assert c['HOST'] == '0.0.0.0'
     assert c['PORT'] == 8080
+
+
+def test_case_sensitivity():
+    c = Config()
+    c.init('TEST', str, 'TEST')
+    with pytest.warns(UserWarning):
+        c.init('test', str, 'test')
+    c.load()
+
+    assert c['TEST'] == 'TEST'
+    assert c['test'] == 'test'
+
+
+def test_basic_values_work_without_load():
+    c = Config()
+    c.init('TEST', str, 'TEST')
+    # no load!
+
+    assert c['TEST'] == 'TEST'
+
+
+def test_nonexisting_config_is_missing():
+    c = Config()
+    c.init('TEST', str, 'TEST')
+    c.load()
+
+    assert 'TEST' in c
+    assert 'NOMNOMNOM' not in c
+
+    with pytest.raises(KeyError):
+        c['NOMNOMNOM']