test: Added unit tests to MappingUtilities.cs

application/CohortManager/src/Functions/Functions.sln

@@ -210,6 +210,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HealthChecks", "Shared\Heal
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EnumHelperTests", "..\..\..\..\tests\UnitTests\SharedTests\EnumHelperTests\EnumHelperTests.csproj", "{1FCC5D88-C291-46E0-84BE-A8FD465FD509}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MappingUtilitiesTests", "..\..\..\..\tests\UnitTests\SharedTests\MappingUtilitiesTests\MappingUtilitiesTests.csproj", "{F2DB16E9-F9C5-4E69-909C-D8ACFB8137CB}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -584,6 +586,10 @@ Global
 		{1FCC5D88-C291-46E0-84BE-A8FD465FD509}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{1FCC5D88-C291-46E0-84BE-A8FD465FD509}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{1FCC5D88-C291-46E0-84BE-A8FD465FD509}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F2DB16E9-F9C5-4E69-909C-D8ACFB8137CB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F2DB16E9-F9C5-4E69-909C-D8ACFB8137CB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F2DB16E9-F9C5-4E69-909C-D8ACFB8137CB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F2DB16E9-F9C5-4E69-909C-D8ACFB8137CB}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

application/CohortManager/src/Functions/Shared/Utilities/MappingUtilities.cs

@@ -16,15 +16,16 @@ public static class MappingUtilities
     /// <summary>
     /// Parses flags that can be Y, N, 0 or 1, such as the exception flag
     /// </summary>
-    public static short ParseStringFlag(string flag)
+    public static short ParseStringFlag(string? flag)
     {
-        return flag.ToUpper() switch
+        return flag?.ToUpper() switch
         {
             "0" => 0,
             "1" => 1,
             "Y" => 1,
             "N" => 0,
-            _ => throw new ArgumentException("Invalid input")
+            null => throw new ArgumentException("Invalid input"),
+            _ => throw new ArgumentException("Invalid input"),
         };
     }
 

tests/UnitTests/SharedTests/MappingUtilitiesTests/MappingUtilitiesTests.cs

@@ -0,0 +1,116 @@
+using NHS.CohortManager.Shared.Utilities;
+
+namespace MappingUtilitiesTests;
+
+[TestClass]
+public class MappingUtilitiesTests
+{
+    private static readonly DateTime expectedResultDT = new DateTime(2000, 01, 01);
+
+    [TestMethod]
+    [DataRow("2000/01/01")]
+    public void ParseNullableDateTime_ValidInput_ReturnDate(string date)
+    {
+        //No Arrange
+        //Act
+        var actual = MappingUtilities.ParseNullableDateTime(date);
+
+        //Assert
+        Assert.AreEqual(actual, expectedResultDT);
+    }
+
+    [TestMethod]
+    [DataRow("2000/0/0")] //Invalid date
+    [DataRow(null)] //Null input
+    public void ParseNullableDateTime_InvalidInput_ReturnNull(string date)
+    {
+        //No Arrange
+        //Act
+        var actual = MappingUtilities.ParseNullableDateTime(date);
+
+        //Assert
+        Assert.IsNull(actual);
+    }
+
+    [TestMethod]
+    [DataRow("0",(short)0)] 
+    [DataRow("1",(short)1)] 
+    [DataRow("N",(short)0)] 
+    [DataRow("Y",(short)1)] 
+    public void ParseStringFlag_ValidInput_ReturnDate(string flag, short expectedResult)
+    {   
+        //No Arrange
+        //Act
+        short actual = MappingUtilities.ParseStringFlag(flag);
+
+        //Assert
+        Assert.AreEqual(actual, expectedResult);
+    }
+
+    [TestMethod]
+    [DataRow("W")]
+    [DataRow(null)]
+    public void ParseStringFlag_InvalidInput_ReturnArguementError(string flag)
+    {
+        //No Arrange or Act
+        //Assert
+        var exception = Assert.ThrowsException<ArgumentException>(() => MappingUtilities.ParseStringFlag(flag));
+        Assert.AreEqual("Invalid input", exception.Message);
+    }
+
+    [TestMethod]
+    [DataRow("01/01/2000")] // dd/mm/yyyy
+    [DataRow("20000101")] // yyyymmdd
+    [DataRow("1/1/2000")] // d/m/yyyy
+    [DataRow("2000")] //yyyy
+    [DataRow("200001")] //yyyymm
+    public void ParseDates_ValidInput_ReturnDate(string date)
+    {
+        //No Arrange
+        //Act
+        var actual = MappingUtilities.ParseDates(date);
+
+        //Assert
+        Assert.AreEqual(actual, expectedResultDT);
+    }
+
+    [TestMethod]
+    [DataRow("00/00/2000")] // dd/mm/yyyy
+    [DataRow("20000000")] // yyyymmdd
+    [DataRow("0/0/2000")] // d/m/yyyy
+    [DataRow(null)]
+    [DataRow("")]
+    public void ParseDates_InvalidInput_ReturnNull(string date)
+    {
+        //No Arrange
+        //Act
+        var actual = MappingUtilities.ParseDates(date);
+
+        //Assert 
+        Assert.IsNull(actual);
+    }
+
+    [TestMethod]
+    public void FormatDateTime_ValidInput_ReturnDate()
+    {
+        //Arrange
+        string expectedResult = "2000-01-01";
+
+        //Act
+        var actual = MappingUtilities.FormatDateTime(expectedResultDT);
+
+        //Assert 
+        Assert.AreEqual(actual, expectedResult);
+    }
+
+    [TestMethod]
+    public void FormatDateTime_InvalidInput_ReturnNull()
+    {
+        //No Arrange
+        //Act
+        var actual = MappingUtilities.FormatDateTime(null);
+
+        //Assert 
+        Assert.IsNull(actual);
+    }
+}

tests/UnitTests/SharedTests/MappingUtilitiesTests/MappingUtilitiesTests.csproj

@@ -0,0 +1,27 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="3.1.1" />
+    <PackageReference Include="MSTest.TestFramework" Version="3.1.1" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="../../../../application/CohortManager/src/Functions/Shared/Utilities/Utilities.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Microsoft.VisualStudio.TestTools.UnitTesting" />
+  </ItemGroup>
+
+</Project>