Tests for SingleChoice field type

Frontend/CO.CDP.OrganisationApp.Tests/Pages/Forms/FormElementSingleChoiceModelTest.cs

@@ -0,0 +1,92 @@
+using CO.CDP.OrganisationApp.Models;
+using CO.CDP.OrganisationApp.Pages.Forms;
+using FluentAssertions;
+using System.ComponentModel.DataAnnotations;
+
+namespace CO.CDP.OrganisationApp.Tests.Pages.Forms;
+
+public class FormElementSingleChoiceModelTest
+{
+    private readonly FormElementSingleChoiceModel _model;
+
+    public FormElementSingleChoiceModelTest()
+    {
+        _model = new FormElementSingleChoiceModel();
+        _model.Options = new FormQuestionOptions() { Choices = ["Option 1", "Option 2", "Option 3"] } ;
+    }
+
+    [Theory]
+    [InlineData(null, null)]
+    [InlineData(" ", null)]
+    [InlineData("yes", null)]
+    [InlineData("no", null)]
+    [InlineData("Option 1", "Option 1")]
+    [InlineData("Option 2", "Option 2")]
+    [InlineData("Option 3", "Option 3")]
+    public void GetAnswer_GetsExpectedFormAnswer(string? input, string? expected)
+    {
+        _model.SelectedOption = input;
+
+        var answer = _model.GetAnswer();
+
+        if (expected == null)
+        {
+            answer.Should().BeNull();
+        }
+        else
+        {
+            answer.Should().NotBeNull();
+            answer!.OptionValue.Should().Be(expected);
+        }
+    }
+
+    [Theory]
+    [InlineData(null, null)]
+    [InlineData(" ", null)]
+    [InlineData("yes", null)]
+    [InlineData("no", null)]
+    [InlineData("Option 1", "Option 1")]
+    [InlineData("Option 2", "Option 2")]
+    [InlineData("Option 3", "Option 3")]
+    public void SetAnswer_SetsExpectedOption(string? selectedOption, string? expected)
+    {
+        var answer = new FormAnswer { OptionValue = selectedOption };
+
+        _model.SetAnswer(answer);
+
+        if (expected == null)
+        {
+            _model.SelectedOption.Should().BeNull();
+        }
+        else
+        {
+            _model.SelectedOption.Should().NotBeNull();
+            _model.SelectedOption.Should().Be(expected);
+        }
+    }
+
+    [Theory]
+    [InlineData(null, "Select an option")]
+    [InlineData(" ", "Select an option")]
+    [InlineData("yes", "Invalid option selected")]
+    [InlineData("no", "Invalid option selected")]
+    [InlineData("Option 1", null)]
+    [InlineData("Option 2", null)]
+    [InlineData("Option 3", null)]
+    public void Validate_ReturnsExpectedResults(string? selectedOption, string? expectedErrorMessage)
+    {
+        _model.SelectedOption = selectedOption;
+
+        var validationResults = _model.Validate(new ValidationContext(_model)).ToList();
+
+        if (expectedErrorMessage != null)
+        {
+            validationResults.Should().ContainSingle();
+            validationResults.First().ErrorMessage.Should().Be(expectedErrorMessage);
+        }
+        else
+        {
+            validationResults.Should().BeEmpty();
+        }
+    }
+}

Frontend/CO.CDP.OrganisationApp/Pages/Forms/FormElementSingleChoiceModel.cs

@@ -12,12 +12,21 @@ public class FormElementSingleChoiceModel : FormElementModel, IValidatableObject
 
     public override FormAnswer? GetAnswer()
     {
-        return string.IsNullOrWhiteSpace(SelectedOption) ? null : new FormAnswer { OptionValue = SelectedOption };
+        if(
+            SelectedOption != null
+            && Options?.Choices != null
+            && Options.Choices.Contains(SelectedOption)
+         )
+        {
+            return new FormAnswer { OptionValue = SelectedOption };
+        }
+
+        return null;
     }
 
     public override void SetAnswer(FormAnswer? answer)
     {
-        if (answer?.OptionValue != null)
+        if (answer?.OptionValue != null && Options?.Choices != null && Options.Choices.Contains(answer.OptionValue))
         {
             SelectedOption = answer.OptionValue;
         }
@@ -28,7 +37,14 @@ public IEnumerable<ValidationResult> Validate(ValidationContext validationContex
 
         if (string.IsNullOrWhiteSpace(SelectedOption))
         {
-            yield return new ValidationResult("All information is required on this page", new[] { nameof(SelectedOption) });
+            yield return new ValidationResult("Select an option", new[] { nameof(SelectedOption) });
+            yield break;
+        }
+
+        if(Options?.Choices == null || (SelectedOption != null && !Options.Choices.Contains(SelectedOption)))
+        {
+            yield return new ValidationResult("Invalid option selected", new[] { nameof(SelectedOption) });
+            yield break;
         }
     }
 }