Improve TimeUnit parsing: add early null/empty checks, use normalized values consistently, and add comprehensive whitespace/special character tests

Co-authored-by: niemyjski <[email protected]>

Author: Copilot

src/Exceptionless.DateTimeExtensions/TimeUnit.cs

@@ -28,28 +28,32 @@ public static bool TryParse(string value, out TimeSpan? time)
 
     private static TimeSpan? ParseTime(string value)
     {
+        if (String.IsNullOrEmpty(value))
+            return null;
+
+        string normalized = value.Trim();
+        if (String.IsNullOrEmpty(normalized))
+            return null;
+
         // bail if we have any weird characters
         foreach (char c in value)
             if (!Char.IsLetterOrDigit(c) && c != '-' && c != '+' && !Char.IsWhiteSpace(c))
                 return null;
 
-        // compare using the original value as uppercase M could mean months.
-        string normalized = value.Trim();
-        
         // Handle years (y) - using average days in a year
-        if (value.EndsWith("y") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int years))
+        if (normalized.EndsWith("y") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int years))
             return new TimeSpan((int)(years * TimeSpanExtensions.AvgDaysInAYear), 0, 0, 0);
 
         // Handle months (M) - using average days in a month, case-sensitive uppercase M
-        if (value.EndsWith("M") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int months))
+        if (normalized.EndsWith("M") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int months))
             return new TimeSpan((int)(months * TimeSpanExtensions.AvgDaysInAMonth), 0, 0, 0);
 
         // Handle weeks (w)
-        if (value.EndsWith("w") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int weeks))
+        if (normalized.EndsWith("w") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int weeks))
             return new TimeSpan(weeks * 7, 0, 0, 0);
 
         // Handle minutes (m) - lowercase m for minutes
-        if (value.EndsWith("m") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int minutes))
+        if (normalized.EndsWith("m") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int minutes))
             return new TimeSpan(0, minutes, 0);
 
         if (normalized.EndsWith("h") && Int32.TryParse(normalized.Substring(0, normalized.Length - 1), out int hours))

tests/Exceptionless.DateTimeExtensions.Tests/TimeUnitTests.cs

@@ -27,6 +27,11 @@ public class TimeUnitTests
         ["1y", new TimeSpan((int)TimeSpanExtensions.AvgDaysInAYear, 0, 0, 0)],
         ["2y", new TimeSpan((int)(2 * TimeSpanExtensions.AvgDaysInAYear), 0, 0, 0)],
         ["-1y", new TimeSpan((int)(-1 * TimeSpanExtensions.AvgDaysInAYear), 0, 0, 0)],
+        // Whitespace trimming tests
+        [" 1y ", new TimeSpan((int)TimeSpanExtensions.AvgDaysInAYear, 0, 0, 0)],
+        ["  2M  ", new TimeSpan((int)(2 * TimeSpanExtensions.AvgDaysInAMonth), 0, 0, 0)],
+        ["\t3w\t", new TimeSpan(21, 0, 0, 0)],
+        [" -1y ", new TimeSpan((int)(-1 * TimeSpanExtensions.AvgDaysInAYear), 0, 0, 0)],
     };
 
     [Theory]
@@ -42,6 +47,13 @@ public void CanParse(string value, TimeSpan expected)
     [InlineData("1234")] // missing unit
     [InlineData("12unknownunit")]
     [InlineData("12h.")]
+    [InlineData("")] // empty string
+    [InlineData("   ")] // whitespace only
+    [InlineData("\t\t")] // tabs only
+    [InlineData("1y@")] // special character after unit
+    [InlineData("1M!")] // special character after unit
+    [InlineData("1w#")] // special character after unit
+    [InlineData("1@y")] // special character in middle
     public void VerifyParseFailure(string value)
     {
         Assert.ThrowsAny<Exception>(() => TimeUnit.Parse(value));
@@ -68,6 +80,19 @@ public void VerifyParseFailure(string value)
     [InlineData("1y", true)]
     [InlineData("2y", true)]
     [InlineData("-1y", true)]
+    // Whitespace tests
+    [InlineData(" 1y ", true)]
+    [InlineData("  2M  ", true)]
+    [InlineData("\t3w\t", true)]
+    [InlineData(" -1M ", true)]
+    // Special character and edge case tests
+    [InlineData("", false)]
+    [InlineData("   ", false)]
+    [InlineData("\t\t", false)]
+    [InlineData("1y@", false)]
+    [InlineData("1M!", false)]
+    [InlineData("1w#", false)]
+    [InlineData("1@y", false)]
     [InlineData(null, false)]
     [InlineData("1.234h", false)] // fractional time
     [InlineData("1234", false)] // missing unit