Merge pull request #908 from VitaliyKurokhtin/apim-hexstring-notation-support

Adding support to write c-style hex strings as strings

Author: baywet

src/Microsoft.OpenApi/Writers/SpecialCharacterStringExtensions.cs

@@ -187,9 +187,10 @@ internal static string GetYamlCompatibleString(this string input)
                 return $"'{input}'";
             }
 
-            // If string can be mistaken as a number, a boolean, or a timestamp,
-            // wrap it in quote to indicate that this is indeed a string, not a number, a boolean, or a timestamp
+            // If string can be mistaken as a number, c-style hexadecimal notation, a boolean, or a timestamp,
+            // wrap it in quote to indicate that this is indeed a string, not a number, c-style hexadecimal notation, a boolean, or a timestamp
             if (decimal.TryParse(input, NumberStyles.Float, CultureInfo.InvariantCulture, out var _) ||
+                IsHexadecimalNotation(input) ||
                 bool.TryParse(input, out var _) ||
                 DateTime.TryParse(input, out var _))
             {
@@ -225,5 +226,10 @@ internal static string GetJsonCompatibleString(this string value)
 
             return $"\"{value}\"";
         }
+
+        internal static bool IsHexadecimalNotation(string input)
+        {
+            return input.StartsWith("0x") && int.TryParse(input.Substring(2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var _);
+        }
     }
 }

test/Microsoft.OpenApi.Tests/Writers/OpenApiWriterSpecialCharacterTests.cs

@@ -38,6 +38,7 @@ from inputExpected in new[] {
                        new[]{ "Test\\Test", "\"Test\\\\Test\""},
                        new[]{ "Test\"Test", "\"Test\\\"Test\""},
                        new[]{ "StringsWith\"Quotes\"", "\"StringsWith\\\"Quotes\\\"\""},
+                       new[]{ "0x1234", "\"0x1234\""},
                      }
                     from shouldBeTerse in shouldProduceTerseOutputValues
                     select new object[] { inputExpected[0], inputExpected[1], shouldBeTerse };
@@ -79,6 +80,7 @@ public void WriteStringWithSpecialCharactersAsJsonWorks(string input, string exp
         [InlineData("trailingspace ", " 'trailingspace '")]
         [InlineData("     trailingspace", " '     trailingspace'")]
         [InlineData("terminal:", " 'terminal:'")]
+        [InlineData("0x1234", " '0x1234'")]
         public void WriteStringWithSpecialCharactersAsYamlWorks(string input, string expected)
         {
             // Arrange