add draft for config schema validation

tests/schema_validation.lua

@@ -0,0 +1,43 @@
+TestConfigSchemaValidator = {}
+
+local config = require('config')
+
+local function len(t)
+  local count = 0
+  for _ in pairs(t) do count = count + 1 end
+  return count
+end
+
+function pprint(t, ident)
+    local ident = ident or 0
+    if type(t) == 'table' then
+        local count = 0
+        for k, v in pairs(t) do
+            print(string.rep('\t', ident) .. k)
+            pprint(v, ident + 1)
+            count = count + 1
+        end
+        if count == 0 then
+            print('<empty table>')
+        end
+    else
+        print(string.rep('\t', ident) .. tostring(t))
+    end
+end
+
+function TestConfigSchemaValidator:testBasicFields()
+    local errors = config.validateSchema({a={type='string'}}, {a='test'})
+    lu.assertIs(len(errors), 0)
+    local errors = config.validateSchema({a={type='number'}}, {a=123})
+    lu.assertIs(len(errors), 0)
+    local errors = config.validateSchema({a={type='string'}}, {a=123})
+    lu.assertIs(len(errors), 1)
+end
+
+function TestConfigSchemaValidator:testList()
+    local errors = config.validateSchema({a={type='list', schema={type='number'}}}, {a={1,2,3}})
+    lu.assertIs(len(errors), 0)
+
+    local errors = config.validateSchema({a={type='list', schema={type='number'}}}, {a={1,2,3,'asd'}})
+    lu.assertIs(len(errors), 1)
+end