Float and Decimal values not fully validated

I've noticed an anomaly in the validation of input for float and decimal field types.

If you set up a Float or Decimal field with default values (our dev system, where I discovered this, had a minimum value of 0, but that's the only non-default change I made), you will see that you if you enter a value with anything but numeric digits or decimal points, validation correctly rejects the input.

However, if you "accidentally" enter something like 1..5698, in a "Decimal" field, the value is accepted, but stored/displayed as:
1.00

Entry of 1.5.698 results in

1.50<code> being saved... so entry is simply truncated at the second decimal. Where this could pose a problem is with European users on a site configured to use the decimal point (.) as the decimal separator instead of comma (,). Since they enter a point instead of a "thousands" separator, an accidental entry including a point twice would result in completely wrong values being stored (i.e. if the user remembers to use the point separator for the decimal, but still forgets and copies a value with a thousands (.) separator.)
Here: <code>1.569.63

(intended, perhaps, as 1569.63 is stored as 1.57.

If you enter the same in a "Float" field, nothing is stored and the content is not saved; you will get an error something like this:
PDOException: SQLSTATE[01000]: Warning: 1265 Data truncated for column 'field_float_test_value' at row 1: INSERT INTO {field_data_field_float_test} (entity_type, entity_id, revision_id, bundle, delta, language, field_float_test_value) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6); Array ( [:db_insert_placeholder_0] => node [:db_insert_placeholder_1] => 6 [:db_insert_placeholder_2] => 6 [:db_insert_placeholder_3] => article [:db_insert_placeholder_4] => 0 [:db_insert_placeholder_5] => und [:db_insert_placeholder_6] => 1..5698 ) in field_sql_storage_field_storage_write() (line 425 of /home/lmontgomery/workspace/drupal7/modules/field/modules/field_sql_storage/field_sql_storage.module).

Steps to reproduce (tried in both 7.0 and dev)
1. Install Drupal with minimal settings and turn on the Field UI and Number modules.
2. Create a simple content type: Float Test
3. Add new field:
Label: Float Test
field name: field_float_test
Type: Float
Widget: Text Field

Field Settings: Decimal Point (decimal marker)
Minimum: 0

4. Add new field:
Label: Decimal Test
field name: field_decimal_test
Type: Decimal
Widget: Text Field

Field Settings: Decimal Point (decimal marker)
Minimum: 0

Attempt to create content (using one field or the other) and test... If you try only Decimal fields, you should see many variations of this result in data being stored, albeit probably not in the way the user meant. For most such content, you should see a similar SQL error to the one pasted above.

I'm attaching a patch which extends the number.test (found in modules/field/modules/number) to more-or-less replicate the issue described (at least with "Decimal" values). This "patch" does not "fix" anything. It just provides other testers and more experienced core developers with a way to simply replicate at least some of this issue. (Perhaps I'll see if I can write a proper patch to fix the issue, but this is a start).

I've also attached the number.test file (already patched), in case that's more appropriate.