Use specified culture/format provider when provided to CalDateTime.ToString

src/Ical.Net.CoreUnitTests/CalDateTimeTests.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using Ical.Net.CalendarComponents;
 using Ical.Net.DataTypes;
 using NUnit.Framework;
@@ -150,5 +151,36 @@ public static IEnumerable<ITestCaseData> DateTimeKindOverrideTestCases()
  .Returns(DateTimeKind.Unspecified)
  .SetName("DateTime with Kind = Unspecified and null tzid returns DateTimeKind.Unspecified");
  }
+
+ [Test, TestCaseSource(nameof(ToStringTestCases))]
+ public string ToStringTests(DateTime localDateTime, string format, IFormatProvider formatProvider)
+ => new CalDateTime(localDateTime, "Pacific/Auckland").ToString(format, formatProvider);
+
+ public static IEnumerable<ITestCaseData> ToStringTestCases()
+ {
+ yield return new TestCaseData(new DateTime(2022, 8, 30, 10, 30, 0), null, null)
+ .Returns($"{new DateTime(2022, 8, 30, 10, 30, 0)} Pacific/Auckland")
+ .SetName("Date and time with current culture formatting returns string using BCL current culture formatted date and time");
+
+ yield return new TestCaseData(new DateTime(2022, 8, 30), null, null)
+ .Returns($"{new DateTime(2022, 8, 30):d} Pacific/Auckland")
+ .SetName("Date only with current culture formatting returns string using BCL current culture formatted date");
+
+ yield return new TestCaseData(new DateTime(2022, 8, 30, 10, 30, 0), "o", null)
+ .Returns("2022-08-30T10:30:00.0000000+12:00 Pacific/Auckland")
+ .SetName("Date and time formatted using format string with no culture returns string using BCL formatter");
+
+ yield return new TestCaseData(new DateTime(2022, 8, 30), "o", null)
+ .Returns("2022-08-30T00:00:00.0000000+12:00 Pacific/Auckland")
+ .SetName("Date and time formatted using format string with no culture returns string using BCL formatter");
+
+ yield return new TestCaseData(new DateTime(2022, 8, 30, 10, 30, 0), null, CultureInfo.InvariantCulture)
+ .Returns("08/30/2022 10:30:00 Pacific/Auckland")
+ .SetName("Date and time with format provider");
+
+ yield return new TestCaseData(new DateTime(2022, 8, 30), null, CultureInfo.InvariantCulture)
+ .Returns("08/30/2022 Pacific/Auckland")
+ .SetName("Date only with current format provider");
+ }
  }
 }

src/Ical.Net/DataTypes/CalDateTime.cs

@@ -535,13 +535,13 @@ public string ToString(string format, IFormatProvider formatProvider)
  }
  if (HasTime && HasDate)
  {
- return Value + tz;
+ return Value.ToString(formatProvider) + tz;
  }
  if (HasTime)
  {
  return Value.TimeOfDay + tz;
  }
- return Value.ToString("d") + tz;
+ return Value.ToString("d", formatProvider) + tz;
  }
  }
 }