Guarantees zero percent on missing sitemap key

Ensures that the FindPercentComplete method returns "0.00"
when a key is not found in the sitemap, preventing potential
incorrect calculations or errors.

Author: BenjaminMichaelis

EssentialCSharp.Web.Tests/SiteMappingTests.cs

@@ -137,4 +137,16 @@ public void FindPercentComplete_EmptySiteMappings_ReturnsZeroPercent()
         // Assert
         Assert.Equal("0.00", percent);
     }
+
+    [Fact]
+    public void FindPercentComplete_KeyNotFound_ReturnsZeroPercent()
+    {
+        // Arrange
+
+        // Act
+        string? percent = GetSiteMap().FindPercentComplete("non-existent-key");
+
+        // Assert
+        Assert.Equal("0.00", percent);
+    }
 }

EssentialCSharp.Web/Extensions/SiteMappingListExtensions.cs

@@ -64,10 +64,11 @@ public static class SiteMappingListExtensions
                 }
             }
         }
-        if (overallMappingCount is 0)
+        if (overallMappingCount is 0 || !currentPageFound)
         {
             return "0.00";
         }
+
         double result = (double)currentMappingCount / overallMappingCount * 100;
         return string.Format(CultureInfo.InvariantCulture, "{0:0.00}", result);
     }