Add character count model binding integration tests (#443)

* Initial plan

* Add character count model binding integration tests

Co-authored-by: gunndabad <2041280+gunndabad@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: gunndabad <2041280+gunndabad@users.noreply.github.com>

Author: Copilot

tests/GovUk.Frontend.AspNetCore.IntegrationTests/TagHelperModelBindingTests/CharacterCount.cshtml

@@ -0,0 +1,3 @@
+@model GovUk.Frontend.AspNetCore.IntegrationTests.TagHelperModelBindingTests.CharacterCountTestsModel
+
+<govuk-character-count for="Text" max-length="200" />

tests/GovUk.Frontend.AspNetCore.IntegrationTests/TagHelperModelBindingTests/CharacterCountOverridden.cshtml

@@ -0,0 +1,8 @@
+@model GovUk.Frontend.AspNetCore.IntegrationTests.TagHelperModelBindingTests.CharacterCountTestsModel
+
+<govuk-character-count for="Text" name="OverriddenName" id="OverriddenId" max-length="200">
+    <govuk-character-count-label>Overridden label</govuk-character-count-label>
+    <govuk-character-count-hint>Overridden hint</govuk-character-count-hint>
+    <govuk-character-count-error-message>Overridden error message</govuk-character-count-error-message>
+    <govuk-character-count-value>Overridden value</govuk-character-count-value>
+</govuk-character-count>

tests/GovUk.Frontend.AspNetCore.IntegrationTests/TagHelperModelBindingTests/Tests.cs

@@ -217,6 +217,50 @@ public async Task TextareaOverridden_RendersCorrectly()
         var errorMessage = page.Locator(".govuk-error-message").First;
         Assert.Equal("Error: Overridden error message", await errorMessage.TextContentAsync());
     }
+
+    [Fact]
+    public async Task CharacterCount_RendersCorrectly()
+    {
+        var page = await fixture.Browser!.NewPageAsync();
+        await page.GotoAsync($"{ServerFixture.BaseUrl}/ModelBindingTests/CharacterCount");
+
+        var textarea = page.Locator("textarea").First;
+        Assert.Equal("Text", await textarea.GetAttributeAsync("name"));
+        Assert.Equal("Text", await textarea.GetAttributeAsync("id"));
+        Assert.Equal("Model value", await textarea.InputValueAsync());
+
+        var label = page.Locator("label").First;
+        Assert.Equal("Text", await label.GetAttributeAsync("for"));
+        Assert.Equal("ModelMetadata display name", await label.InnerTextAsync());
+
+        var hint = page.Locator(".govuk-hint").First;
+        Assert.Equal("ModelMetadata description", await hint.InnerTextAsync());
+
+        var errorMessage = page.Locator(".govuk-error-message").First;
+        Assert.Equal("Error: Model error message", await errorMessage.TextContentAsync());
+    }
+
+    [Fact]
+    public async Task CharacterCountOverridden_RendersCorrectly()
+    {
+        var page = await fixture.Browser!.NewPageAsync();
+        await page.GotoAsync($"{ServerFixture.BaseUrl}/ModelBindingTests/CharacterCountOverridden");
+
+        var textarea = page.Locator("textarea").First;
+        Assert.Equal("OverriddenName", await textarea.GetAttributeAsync("name"));
+        Assert.Equal("OverriddenId", await textarea.GetAttributeAsync("id"));
+        Assert.Equal("Overridden value", await textarea.InputValueAsync());
+
+        var label = page.Locator("label").First;
+        Assert.Equal("OverriddenId", await label.GetAttributeAsync("for"));
+        Assert.Equal("Overridden label", await label.InnerTextAsync());
+
+        var hint = page.Locator(".govuk-hint").First;
+        Assert.Equal("Overridden hint", await hint.InnerTextAsync());
+
+        var errorMessage = page.Locator(".govuk-error-message").First;
+        Assert.Equal("Error: Overridden error message", await errorMessage.TextContentAsync());
+    }
 }
 
 [Route("/[controller]/[action]")]
@@ -284,6 +328,20 @@ public IActionResult TextareaOverridden()
         ModelState.AddModelError(nameof(TextareaTestsModel.Text), "Model error message");
         return View(new TextareaTestsModel { Text = "Model value" });
     }
+
+    [HttpGet]
+    public IActionResult CharacterCount()
+    {
+        ModelState.AddModelError(nameof(CharacterCountTestsModel.Text), "Model error message");
+        return View(new CharacterCountTestsModel { Text = "Model value" });
+    }
+
+    [HttpGet]
+    public IActionResult CharacterCountOverridden()
+    {
+        ModelState.AddModelError(nameof(CharacterCountTestsModel.Text), "Model error message");
+        return View(new CharacterCountTestsModel { Text = "Model value" });
+    }
 }
 
 public record TextInputTestsModel
@@ -309,3 +367,9 @@ public record TextareaTestsModel
     [Display(Name = "ModelMetadata display name", Description = "ModelMetadata description")]
     public string? Text { get; set; }
 }
+
+public record CharacterCountTestsModel
+{
+    [Display(Name = "ModelMetadata display name", Description = "ModelMetadata description")]
+    public string? Text { get; set; }
+}