Fix phone number test template (#555)

Author: TheRealOwenRees

exercises/practice/phone-number/.meta/example.ml

@@ -25,8 +25,9 @@ let number s =
   else
     let s = String.filter ~f:(Char.is_digit) s in
     match String.length s with
+    | x when x < 10                        -> Error "must not be fewer than 10 digits"
     | 10                                   -> check_valid_first_digits s
     | 11 when Char.(String.get s 0 = '1')  -> check_valid_first_digits (String.drop_prefix s 1)
     | 11                                   -> Error "11 digits must start with 1"
-    | x when x > 11                        -> Error "more than 11 digits"
+    | x when x > 11                        -> Error "must not be greater than 11 digits"
 | _ -> Error "incorrect number of digits"

exercises/practice/phone-number/dune-project

@@ -1,2 +1,2 @@
 (lang dune 1.1)
-(version 1.7.0)
+(version 1.0)

exercises/practice/phone-number/test.ml

@@ -1,4 +1,4 @@
-(* phone-number - 1.7.0 *)
+(* phone-number - 1.0 *)
 open Base
 open OUnit2
 open Phone_number
@@ -18,19 +18,19 @@ let tests = [
   "cleans numbers with multiple spaces" >::
   ae (Ok "2234567890") (number "223 456   7890   ");
   "invalid when 9 digits" >::
-  ae (Error "incorrect number of digits") (number "123456789");
+  ae (Error "must not be fewer than 10 digits") (number "123456789");
   "invalid when 11 digits does not start with a 1" >::
   ae (Error "11 digits must start with 1") (number "22234567890");
   "valid when 11 digits and starting with 1" >::
   ae (Ok "2234567890") (number "12234567890");
   "valid when 11 digits and starting with 1 even with punctuation" >::
   ae (Ok "2234567890") (number "+1 (223) 456-7890");
   "invalid when more than 11 digits" >::
-  ae (Error "more than 11 digits") (number "321234567890");
+  ae (Error "must not be greater than 11 digits") (number "321234567890");
   "invalid with letters" >::
-  ae (Error "letters not permitted") (number "123-abc-7890");
+  ae (Error "letters not permitted") (number "523-abc-7890");
   "invalid with punctuations" >::
-  ae (Error "punctuations not permitted") (number "123-@:!-7890");
+  ae (Error "punctuations not permitted") (number "523-@:!-7890");
   "invalid if area code starts with 0" >::
   ae (Error "area code cannot start with zero") (number "(023) 456-7890");
   "invalid if area code starts with 1" >::