convert before validate, also fix two-space thing

src/attr/_make.py

@@ -83,12 +83,11 @@ def attr(default=NOTHING, validator=None,
     :param init: Include this attribute in the generated ``__init__`` method.
     :type init: bool
 
-    :param convert: :func:`callable` that is called by ``attrs``-generated
-        ``__init__`` methods to convert attribute's value to the desired
-        format. It is given the passed-in value, and the returned value will
-        be used as the new value of the attribute.
-    :type convert: callable
-
+    :param callable convert: :func:`callable` that is called by
+        ``attrs``-generated ``__init__`` methods to convert attribute's value
+        to the desired format.  It is given the passed-in value, and the
+        returned value will be used as the new value of the attribute. The
+        value is converted before being passed to the validator, if any.
     """
     return _CountingAttr(
         default=default,
@@ -461,10 +460,10 @@ else:
                 arg_name=arg_name,
             ))
 
-    if has_validator:
-        lines.append("validate(self)")
     if has_convert:
         lines.append("_convert(self)")
+    if has_validator:
+        lines.append("validate(self)")
 
     return """\
 def __init__(self, {args}):

tests/test_make.py

@@ -406,9 +406,9 @@ class TestConvert(object):
         assert c.x == 2
         assert c.y == 2
 
-    def test_convert_after_validate(self):
+    def test_convert_before_validate(self):
         """
-        Validation happens before conversion.
+        Validation happens after conversion.
         """
         def validator(inst, attr, val):
             raise RuntimeError("foo")
@@ -416,7 +416,7 @@ class TestConvert(object):
             "C",
             {"x": attr(validator=validator, convert=lambda v: 1 / 0),
              "y": attr()})
-        with pytest.raises(RuntimeError):
+        with pytest.raises(ZeroDivisionError):
             C(1, 2)