Start defining type classes

2 files changed, 186 insertions, 0 deletions

diff --git a/lesana/types.py b/lesana/types.py
new file mode 100644
index 0000000..e093c9f
--- /dev/null
+++ b/lesana/types.py
@@ -0,0 +1,98 @@
+"""
+Type checkers for lesana fields.
+
+Warning: this part of the code is still in flux and it may change
+significantly in a future release.
+"""
+import decimal
+
+
+class LesanaType:
+    """
+    Base class for lesana field types.
+    """
+    def load(self, data):
+        raise NotImplementedError
+
+    def empty(self):
+        raise NotImplementedError
+
+
+class LesanaString(LesanaType):
+    """
+    A string of unicode text
+    """
+    name = 'string'
+
+    def load(self, data):
+        return str(data)
+
+    def empty(self):
+        return ""
+
+
+class LesanaText(LesanaString):
+    """
+    A longer block of unicode text
+    """
+    name = 'text'
+
+
+class LesanaInt(LesanaType):
+    """
+    An integer number
+    """
+    name = "integer"
+
+    def load(self, data):
+        try:
+            return int(data)
+        except ValueError:
+            raise LesanaValueError(
+                "Invalid value for integer field: {}".format(data)
+            )
+
+    def empty(self):
+        return 0
+
+
+class LesanaFloat(LesanaType):
+    """
+    A floating point number
+    """
+    name = "float"
+
+    def load(self, data):
+        try:
+            return float(data)
+        except ValueError:
+            raise LesanaValueError(
+                "Invalid value for float field: {}".format(data)
+            )
+
+    def empty(self):
+        return 0.0
+
+
+class LesanaDecimal(LesanaType):
+    """
+    A floating point number
+    """
+    name = "float"
+
+    def load(self, data):
+        try:
+            return decimal.Decimal(data)
+        except decimal.InvalidOperation:
+            raise LesanaValueError(
+                "Invalid value for float field: {}".format(data)
+            )
+
+    def empty(self):
+        return decimal.Decimal(0)
+
+
+class LesanaValueError(ValueError):
+    """
+    Raised in case of validation errors.
+    """
diff --git a/tests/test_types.py b/tests/test_types.py
new file mode 100644
index 0000000..907be20
--- /dev/null
+++ b/tests/test_types.py
@@ -0,0 +1,88 @@
+import decimal
+import unittest
+
+from lesana import types
+
+
+class testTypes(unittest.TestCase):
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def test_string(self):
+        checker = types.LesanaString()
+
+        s = checker.empty()
+        self.assertEqual(s, "")
+
+        s = checker.load("Hello World!")
+        self.assertEqual(s, "Hello World!")
+
+    def test_text(self):
+        checker = types.LesanaText()
+
+        s = checker.empty()
+        self.assertEqual(s, "")
+
+        s = checker.load("Hello World!")
+        self.assertEqual(s, "Hello World!")
+
+    def test_int(self):
+        checker = types.LesanaInt()
+
+        v = checker.empty()
+        self.assertEqual(v, 0)
+
+        v = checker.load("10")
+        self.assertEqual(v, 10)
+
+        v = checker.load(10.5)
+        self.assertEqual(v, 10)
+
+        for d in ("ten", "10.5"):
+            with self.assertRaises(types.LesanaValueError):
+                checker.load(d)
+
+    def test_float(self):
+        checker = types.LesanaFloat()
+
+        v = checker.empty()
+        self.assertEqual(v, 0.0)
+
+        v = checker.load("10")
+        self.assertEqual(v, 10)
+
+        v = checker.load(10.5)
+        self.assertEqual(v, 10.5)
+
+        v = checker.load("10.5")
+        self.assertEqual(v, 10.5)
+
+        for d in ("ten"):
+            with self.assertRaises(types.LesanaValueError):
+                checker.load(d)
+
+    def test_decimal(self):
+        checker = types.LesanaDecimal()
+
+        v = checker.empty()
+        self.assertEqual(v, decimal.Decimal(0))
+
+        v = checker.load("10")
+        self.assertEqual(v, decimal.Decimal(10))
+
+        v = checker.load(10.5)
+        self.assertEqual(v, decimal.Decimal(10.5))
+
+        v = checker.load("10.5")
+        self.assertEqual(v, decimal.Decimal(10.5))
+
+        for d in ("ten"):
+            with self.assertRaises(types.LesanaValueError):
+                checker.load(d)
+
+
+if __name__ == '__main__':
+    unittest.main()