microsoft · baywet · Oct 19, 2022 · Sep 19, 2022
diff --git a/src/Microsoft.OpenApi/Writers/SpecialCharacterStringExtensions.cs b/src/Microsoft.OpenApi/Writers/SpecialCharacterStringExtensions.cs
@@ -192,7 +192,7 @@ internal static string GetYamlCompatibleString(this string input)
            if (decimal.TryParse(input, NumberStyles.Float, CultureInfo.InvariantCulture, out var _) ||
                IsHexadecimalNotation(input) ||
                bool.TryParse(input, out var _) ||
-                DateTime.TryParse(input, out var _))
+                DateTime.TryParse(input, CultureInfo.InvariantCulture, DateTimeStyles.None, out var _))
            {
                return $"'{input}'";
            }

diff --git a/test/Microsoft.OpenApi.Tests/Writers/OpenApiWriterSpecialCharacterTests.cs b/test/Microsoft.OpenApi.Tests/Writers/OpenApiWriterSpecialCharacterTests.cs
@@ -148,5 +148,26 @@ public void WriteStringWithNewlineCharactersInArrayAsYamlWorks(string input, str
            // Assert
            actual.Should().Be(expected);
        }
+
+        [Theory]
+        [InlineData("1.8.0", " '1.8.0'", "en-US")]
+        [InlineData("1.8.0", " '1.8.0'", "en-GB")]
+        [InlineData("1.13.0", " '1.13.0'", "en-US")]
+        [InlineData("1.13.0", " '1.13.0'", "en-GB")]
+        public void WriteStringAsYamlDoesNotDependOnSystemCulture(string input, string expected, string culture)
+        {
+            CultureInfo.CurrentCulture = CultureInfo.GetCultureInfo(culture);
+
+            // Arrange
+            var outputStringWriter = new StringWriter(CultureInfo.InvariantCulture);
+            var writer = new OpenApiYamlWriter(outputStringWriter);
+
+            // Act
+            writer.WriteValue(input);
+            var actual = outputStringWriter.GetStringBuilder().ToString();
+
+            // Assert
+            actual.Should().Be(expected);
+        }
    }
 }