From 0ca8ea716e3a6b19b96148b537671a8973c7e679 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Dudak?= <michal@dudak.me>
Date: Wed, 8 Apr 2020 19:00:43 +0200
Subject: [PATCH] Introduced SsnValidator class; returning ValidationResult
 instead of bool

---
 Adia.SsnValidator.Tests/SsnValidatorTests.cs  | 29 +++++++++++
 .../Validators/AhvValidatorTests.cs           | 51 +++++++++++--------
 Adia.SsnValidator/Adia.SsnValidator.csproj    |  4 +-
 Adia.SsnValidator/Properties/AssemblyInfo.cs  |  1 +
 Adia.SsnValidator/SsnValidator.cs             | 12 +++++
 Adia.SsnValidator/SsnValidatorFactory.cs      |  4 +-
 Adia.SsnValidator/ValidationResult.cs         |  9 ++++
 Adia.SsnValidator/Validators/AhvValidator.cs  | 18 ++++---
 Adia.SsnValidator/Validators/IValidator.cs    |  6 +--
 CHANGELOG.md                                  |  5 ++
 10 files changed, 104 insertions(+), 35 deletions(-)
 create mode 100644 Adia.SsnValidator.Tests/SsnValidatorTests.cs
 create mode 100644 Adia.SsnValidator/Properties/AssemblyInfo.cs
 create mode 100644 Adia.SsnValidator/SsnValidator.cs
 create mode 100644 Adia.SsnValidator/ValidationResult.cs

diff --git a/Adia.SsnValidator.Tests/SsnValidatorTests.cs b/Adia.SsnValidator.Tests/SsnValidatorTests.cs
new file mode 100644
index 0000000..1894554
--- /dev/null
+++ b/Adia.SsnValidator.Tests/SsnValidatorTests.cs
@@ -0,0 +1,29 @@
+using System;
+using NUnit.Framework;
+
+namespace Adia.SsnValidator.Tests
+{
+    public class SsnValidatorTests
+    {
+        private SsnValidator _validator;
+
+        [SetUp]
+        public void Setup()
+        {
+            _validator = new SsnValidator();
+        }
+
+        [Test]
+        public void GivenCorrectSwissArguments_ShouldRunSwissSsnValidation()
+        {
+            var result = _validator.Validate("756.4089.0811.50", CountryCode.CH);
+            Assert.AreEqual(result, ValidationResult.Valid);
+        }
+
+        [Test]
+        public void GivenIncorrectCountryCode_ShouldThrowExceptiom()
+        {
+           Assert.Throws<NotSupportedException>(() => _validator.Validate("756.4089.0811.50", (CountryCode) 100));
+        }
+    }
+}
diff --git a/Adia.SsnValidator.Tests/Validators/AhvValidatorTests.cs b/Adia.SsnValidator.Tests/Validators/AhvValidatorTests.cs
index 0e6a233..a13f23c 100644
--- a/Adia.SsnValidator.Tests/Validators/AhvValidatorTests.cs
+++ b/Adia.SsnValidator.Tests/Validators/AhvValidatorTests.cs
@@ -1,9 +1,10 @@
-using Adia.SsnValidator.Validators;
+using System;
+using Adia.SsnValidator;
+using Adia.SsnValidator.Validators;
 using NUnit.Framework;
 
 namespace Adia.Ssn.Tests.Validators
 {
-    [TestFixture]
     public class AhvValidatorTests
     {
         private AhvValidator _validator;
@@ -14,28 +15,34 @@ public void Setup()
             _validator = new AhvValidator();
         }
 
-        [Test]
-        [TestCase("756.4089.0811.50", true)]
-        [TestCase("756.5220.1643.81", true)]
-        [TestCase("756.5837.4745.52", true)]
-        [TestCase("756.1656.9672.13", true)]
-        [TestCase("756.6168.0333.64", true)]
-        [TestCase("756.0246.1057.45", true)]
-        [TestCase("756.8478.9370.66", true)]
-        [TestCase("756.0298.4726.97", true)]
-        [TestCase("756.5113.6381.28", true)]
-        [TestCase("756.5466.9658.89", true)]
-        [TestCase("756.5466.965889", false)]
-        [TestCase("755:5466.9658.89", false)]
-        [TestCase("7561656967213", false)]
-        [TestCase("756.1234.5678.95", false)]
-        [TestCase("7561234567895", false)]
-        [TestCase("75612345648955", false)]
-        public void ValidateAhvNumberAsExpected(string ssn, bool expectedResult)
+        [TestCase("756.4089.0811.50", ValidationResult.Valid)]
+        [TestCase("756.5220.1643.81", ValidationResult.Valid)]
+        [TestCase("756.5837.4745.52", ValidationResult.Valid)]
+        [TestCase("756.1656.9672.13", ValidationResult.Valid)]
+        [TestCase("756.6168.0333.64", ValidationResult.Valid)]
+        [TestCase("756.0246.1057.45", ValidationResult.Valid)]
+        [TestCase("756.8478.9370.66", ValidationResult.Valid)]
+        [TestCase("756.0298.4726.97", ValidationResult.Valid)]
+        [TestCase("756.5113.6381.28", ValidationResult.Valid)]
+        [TestCase("756.5466.9658.89", ValidationResult.Valid)]
+        [TestCase("756.1234.5678.95", ValidationResult.InvalidChecksum)]
+        [TestCase("756.5466.965889", ValidationResult.InvalidFormat)]
+        [TestCase("755:5466.9658.89", ValidationResult.InvalidFormat)]
+        [TestCase("7561656967213", ValidationResult.InvalidFormat)]
+        [TestCase("7561234567895", ValidationResult.InvalidFormat)]
+        [TestCase("75612345648955", ValidationResult.InvalidFormat)]
+        [TestCase("000.4089.0811.50", ValidationResult.InvalidFormat)]
+        [TestCase("", ValidationResult.InvalidFormat)]
+        public void GivenNonNullAhv_ShouldValidateIt(string ssn, ValidationResult expectedResult)
         {
             var result = _validator.Validate(ssn);
-
             Assert.That(result, Is.EqualTo(expectedResult));
         }
+
+        [Test]
+        public void GivenNullAhv_ShouldThrowArgumentNullException()
+        {
+            Assert.Throws<ArgumentNullException>(() => _validator.Validate(null));
+        }
     }
-}
\ No newline at end of file
+}
diff --git a/Adia.SsnValidator/Adia.SsnValidator.csproj b/Adia.SsnValidator/Adia.SsnValidator.csproj
index 2cc4855..a1d0c1c 100644
--- a/Adia.SsnValidator/Adia.SsnValidator.csproj
+++ b/Adia.SsnValidator/Adia.SsnValidator.csproj
@@ -2,10 +2,10 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <Version>0.0.1</Version>
+    <Version>0.1.0</Version>
     <Authors>PiotrSzperka; doodack</Authors>
     <Company>Adia</Company>
-    <Description>C# library for validating SSN number for countries supported by Adia</Description>
+    <Description>C# library for validating Social Security Numbers for countries supported by Adia</Description>
     <Copyright>Adia</Copyright>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <PackageProjectUrl>https://github.com/adia-technology/Adia.SsnValidator</PackageProjectUrl>
diff --git a/Adia.SsnValidator/Properties/AssemblyInfo.cs b/Adia.SsnValidator/Properties/AssemblyInfo.cs
new file mode 100644
index 0000000..e57f045
--- /dev/null
+++ b/Adia.SsnValidator/Properties/AssemblyInfo.cs
@@ -0,0 +1 @@
+[assembly:System.Runtime.CompilerServices.InternalsVisibleTo("Adia.SsnValidator.Tests")]
diff --git a/Adia.SsnValidator/SsnValidator.cs b/Adia.SsnValidator/SsnValidator.cs
new file mode 100644
index 0000000..6684dfe
--- /dev/null
+++ b/Adia.SsnValidator/SsnValidator.cs
@@ -0,0 +1,12 @@
+namespace Adia.SsnValidator
+{
+    public class SsnValidator
+    {
+        public ValidationResult Validate(string ssn, CountryCode country)
+        {
+            var factory = new SsnValidatorFactory();
+            var validator = factory.Create(country);
+            return validator.Validate(ssn);
+        }
+    }
+}
diff --git a/Adia.SsnValidator/SsnValidatorFactory.cs b/Adia.SsnValidator/SsnValidatorFactory.cs
index 23b09ff..feb7aa7 100644
--- a/Adia.SsnValidator/SsnValidatorFactory.cs
+++ b/Adia.SsnValidator/SsnValidatorFactory.cs
@@ -3,7 +3,7 @@
 
 namespace Adia.SsnValidator
 {
-    public class SsnValidatorFactory
+    internal class SsnValidatorFactory
     {
         public IValidator Create(CountryCode country)
         {
@@ -13,7 +13,7 @@ public IValidator Create(CountryCode country)
                     return new AhvValidator();
 
                 default:
-                    throw new NotSupportedException("Your country is not supported");
+                    throw new NotSupportedException($"The provided country ({country}) is not supported.");
             }
         }
     }
diff --git a/Adia.SsnValidator/ValidationResult.cs b/Adia.SsnValidator/ValidationResult.cs
new file mode 100644
index 0000000..b1be9c0
--- /dev/null
+++ b/Adia.SsnValidator/ValidationResult.cs
@@ -0,0 +1,9 @@
+namespace Adia.SsnValidator
+{
+    public enum ValidationResult
+    {
+        Valid,
+        InvalidFormat,
+        InvalidChecksum
+    }
+}
diff --git a/Adia.SsnValidator/Validators/AhvValidator.cs b/Adia.SsnValidator/Validators/AhvValidator.cs
index 73d709e..0a6bdd8 100644
--- a/Adia.SsnValidator/Validators/AhvValidator.cs
+++ b/Adia.SsnValidator/Validators/AhvValidator.cs
@@ -4,14 +4,19 @@
 
 namespace Adia.SsnValidator.Validators
 {
-    public class AhvValidator : IValidator
+    internal sealed class AhvValidator : IValidator
     {
-        public bool Validate(string ahv)
+        public ValidationResult Validate(string ahv)
         {
+            if (ahv == null)
+            {
+                throw new ArgumentNullException(nameof(ahv));
+            }
+
             var regex = new Regex(@"^756\.\d{4}\.\d{4}\.\d{2}$");
-            if(!regex.IsMatch(ahv))
+            if (!regex.IsMatch(ahv))
             {
-                return false;
+                return ValidationResult.InvalidFormat;
             }
 
             var ahv13 = ahv.Where(char.IsDigit).ToArray();
@@ -33,7 +38,8 @@ public bool Validate(string ahv)
             var nextTimesTen = Math.Ceiling(totalChecksum / 10.0) * 10;
             var checksumDigit = (int)nextTimesTen - totalChecksum;
 
-            return checksumDigit == int.Parse(ahv.Last().ToString());
+            var isChecksumCorrect = checksumDigit == int.Parse(ahv.Last().ToString());
+            return isChecksumCorrect ? ValidationResult.Valid : ValidationResult.InvalidChecksum;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Adia.SsnValidator/Validators/IValidator.cs b/Adia.SsnValidator/Validators/IValidator.cs
index c817661..382566f 100644
--- a/Adia.SsnValidator/Validators/IValidator.cs
+++ b/Adia.SsnValidator/Validators/IValidator.cs
@@ -1,7 +1,7 @@
 namespace Adia.SsnValidator.Validators
 {
-    public interface IValidator
+    internal interface IValidator
     {
-        bool Validate(string ssn);
+        ValidationResult Validate(string ssn);
     }
-}
\ No newline at end of file
+}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a40ddc2..cd03bae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.1.0
+
+* **BREAKING CHANGE** Changed the main validation class to be `SsnValidator`. This is the only publicly available class in the library.
+* `SsnValidator.Validate` returns a `ValidationResult` instance that can be used to determine why an SSN is invalid.
+
 ## 0.0.1
 
 Initial version with support for Swiss SSN (AHV).