Bug/i1102 (#1104)

* Fix substitute returning strings when actually an error

* Changed from throw to return. Moved issue test to appropriate location

src/EPPlus/FormulaParsing/Excel/Functions/Text/Substitute.cs

@@ -15,6 +15,7 @@ Date               Author                       Change
 using System.Linq;
 using System.Text;
 using OfficeOpenXml.FormulaParsing.Excel.Functions.Metadata;
+using OfficeOpenXml.FormulaParsing.Exceptions;
 using OfficeOpenXml.FormulaParsing.ExpressionGraph;
 
 namespace OfficeOpenXml.FormulaParsing.Excel.Functions.Text
@@ -28,6 +29,15 @@ internal class Substitute : ExcelFunction
         public override CompileResult Execute(IEnumerable<FunctionArgument> arguments, ParsingContext context)
         {
             ValidateArguments(arguments, 3);
+
+            foreach (var arg in arguments)
+            {
+                if (arg.ValueIsExcelError)
+                {
+                    return new CompileResult(arg.ValueAsExcelErrorValue, DataType.ExcelError);
+                }
+            }
+
             var text = ArgToString(arguments, 0);
             var find = ArgToString(arguments, 1);
             var replaceWith = ArgToString(arguments, 2);

src/EPPlusTest/Issues.cs

@@ -5398,5 +5398,25 @@ void DebugGetFontInfo()
                 SaveAndCleanup(package);
             }
         }
+        [TestMethod]
+        public void i1102()
+        {
+            using (var excel = new ExcelPackage())
+            {
+                var worksheet = excel.Workbook.Worksheets.Add("Test Worksheet");
+                var targetCell = worksheet.Cells[1, 1];
+                var validationCell = worksheet.Cells[1, 2];
+
+                validationCell.Formula = "IFERROR(SUBSTITUTE(RIGHT(A1,LEN(A1)-FIND(\"-\",A1)),\"-\",\"|\"),\"0\")";
+
+                targetCell.Value = "invalid";
+
+                validationCell.Calculate();
+
+                var result = validationCell.GetValue<string>();
+
+                Assert.AreEqual("0", result);
+            }
+        }
     }
 }