Added extension Samordningsnummer with unit tests (#414)

* Added extension Samordningsnummer with unit tests

* Add Samordningsnummer API doc

---------

Co-authored-by: Brian Chavez <bchavez@bitarmory.com>

README.md

@@ -522,6 +522,7 @@ In the examples above, all three alternative styles of using **Bogus** produce t
 	* `Bogus.Person.Cnp()` - Romanian Personal Identification number (CNP)
 * **`using Bogus.Extensions.Sweden;`**
 	* `Bogus.Person.Personnummer()` - Swedish national identity number
+	* `Bogus.Person.Samordningsnummer()` - Swedish coordination number
 * **`using Bogus.Extensions.UnitedKingdom;`**
 	* `Bogus.DataSets.Vehicle.GbRegistrationPlate()` - GB Vehicle Registration Plate
 	* `Bogus.DataSets.Finance.SortCode()` - Banking Sort Code

Source/Bogus.Tests/ExtensionTests/SwedishExtensionTest.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using Bogus.DataSets;
 using Bogus.Extensions.Sweden;
@@ -20,33 +21,73 @@ public void can_create_valid_swedish_personnummer()
    }
 
    [Fact]
-   public void when_person_is_male_second_last_number_is_even()
+   public void can_create_valid_swedish_samordningsnummer()
+   {
+      var f = new Faker("sv");
+      var person = f.Person;
+
+      var samordningsnummer = person.Samordningsnummer();
+
+      CheckLuhn(samordningsnummer.Substring(2)).Should().BeTrue();
+   }
+
+   [Fact]
+   public void personnummer_should_contain_valid_date_of_birth()
    {
       var f = new Faker("sv");
       var person = f.Person;
-      person.Gender = Name.Gender.Male;
 
       var personnummer = person.Personnummer();
+      var (year, month, day) = ExtractDateParts(personnummer);
+      var dateOfBirth = new DateTime(year, month, day);
+
+      dateOfBirth.Date.Should().Be(person.DateOfBirth.Date);
+   }
 
-      var secondLast = int.Parse(personnummer.Substring(personnummer.Length - 2, 1));
+   [Fact]
+   public void samordningsnummer_should_contain_offset_date_of_birth()
+   {
+      var f = new Faker("sv");
+      var person = f.Person;
 
+      var samordningsnummer = person.Samordningsnummer();
+      var (year, month, day) = ExtractDateParts(samordningsnummer);
+      var dateOfBirth = new DateTime(year, month, day - 60);
+
+      dateOfBirth.Date.Should().Be(person.DateOfBirth.Date);
+   }
+
+   [Theory]
+   [InlineData(false)]
+   [InlineData(true)]
+   public void when_person_is_male_second_last_number_is_even(bool isSamordningsnummer)
+   {
+      var f = new Faker("sv");
+      var person = f.Person;
+      person.Gender = Name.Gender.Male;
+
+      var identificationNumber = isSamordningsnummer ? person.Samordningsnummer() : person.Personnummer();
+
+      var secondLast = int.Parse(identificationNumber.Substring(identificationNumber.Length - 2, 1));
 
       secondLast.Should()
          .Match(x => x % 2 == 0)
          .And.BeLessThan(10)
          .And.BeGreaterThan(0);
    }
 
-   [Fact]
-   public void when_person_is_female_second_last_number_is_odd()
+   [Theory]
+   [InlineData(false)]
+   [InlineData(true)]
+   public void when_person_is_female_second_last_number_is_odd(bool isSamordningsnummer)
    {
       var f = new Faker("sv");
       var person = f.Person;
       person.Gender = Name.Gender.Female;
 
-      var personnummer = person.Personnummer();
+      var identificationNumber = isSamordningsnummer ? person.Samordningsnummer() : person.Personnummer();
 
-      var secondLast = int.Parse(personnummer.Substring(personnummer.Length - 2, 1));
+      var secondLast = int.Parse(identificationNumber.Substring(identificationNumber.Length - 2, 1));
 
       secondLast.Should()
          .Match(x => x % 2 == 1)
@@ -65,4 +106,9 @@ private static bool CheckLuhn(string digits)
          )
          .Sum() % 10 == 0;
    }
+
+   private static (int year, int month, int day) ExtractDateParts(string date)
+   {
+      return (int.Parse(date.Substring(0, 4)), int.Parse(date.Substring(4, 2)), int.Parse(date.Substring(6, 2)));
+   }
 }

Source/Bogus/Extensions/Sweden/ExtensionsForSweden.cs

@@ -43,11 +43,46 @@ public static string Personnummer(this Person person)
       return individualNumber;
    }
 
+   /// <summary>
+   /// Swedish coordination number
+   /// </summary>
+   /// <remarks>
+   /// Coordination numbers enable Swedish public authorities and other organisations with a public function 
+   /// to identify people who are not currently – and have never been – registered at an address in Sweden.
+   /// </remarks>
+   public static string Samordningsnummer(this Person person)
+   {
+      const string key = nameof(ExtensionsForSweden) + nameof(Samordningsnummer);
+      if( person.context.ContainsKey(key) )
+      {
+         return person.context[key] as string;
+      }
+
+      /*
+
+          YYYYMMXXBBGC
+          |   | | | ||---> (C)Checksum
+          |   | | | | 
+          |   | | | |----> (G)Gender
+          |   | | |------> (B)Birthplace
+          |   | |--------> (X)Day+60
+          |   |----------> (M)Month
+          |--------------> (Y)Year
+      
+         info: https://skatteverket.se/privat/folkbokforing/samordningsnummer.4.5c281c7015abecc2e201130b.html
+      */
+      var r = person.Random;
+      var individualNumber = GenerateIndividualNumber(r, person.Gender, person.DateOfBirth, 60);
+
+      person.context[key] = individualNumber;
+      return individualNumber;
+   }
 
-   private static string GenerateIndividualNumber(Randomizer r, Gender gender, DateTime dateOfBirth)
+   private static string GenerateIndividualNumber(Randomizer r, Gender gender, DateTime dateOfBirth, int dayOffset = 0)
    {
       var genderNumber = GetGenderNumber(r, gender);
-      var p = dateOfBirth.ToString("yyyyMMddff") + genderNumber;
+      var offsetDay = dateOfBirth.Day + dayOffset;
+      var p = dateOfBirth.ToString("yyyyMM") + offsetDay.ToString("00") + dateOfBirth.ToString("ff") + genderNumber;
       var checksum = GetLuhn(p.Substring(2));
       return p + checksum;
    }