allow conversion from StreamPosition to StreamRevision

src/EventStore.Client.Streams/IWriteResult.cs

@@ -8,7 +8,8 @@ public interface IWriteResult {
 		/// <summary>
 		/// The version the stream is currently at.
 		/// </summary>
-		[Obsolete]
+		[Obsolete("Please use NextExpectedStreamRevision instead. This property will be removed in a future version.",
+			true)]
 		long NextExpectedVersion { get; }
 		/// <summary>
 		/// The <see cref="Position"/> of the <see cref="IWriteResult"/> in the transaction file.

src/EventStore.Client/StreamPosition.cs

@@ -26,6 +26,16 @@ namespace EventStore.Client {
 		public static StreamPosition FromInt64(long value) =>
 			value == -1 ? End : new StreamPosition(Convert.ToUInt64(value));
 
+		/// <summary>
+		/// Creates a <see cref="StreamPosition"/> from a <see cref="StreamRevision"/>.
+		/// </summary>
+		/// <param name="revision"></param>
+		/// <returns></returns>
+		public static StreamPosition FromStreamRevision(StreamRevision revision) => revision.ToUInt64() switch {
+			ulong.MaxValue => throw new ArgumentOutOfRangeException(nameof(revision)),
+			_ => new StreamPosition(revision.ToUInt64())
+		};
+
 		/// <summary>
 		/// Constructs a new <see cref="StreamPosition"/>.
 		/// </summary>
@@ -39,6 +49,12 @@ public StreamPosition(ulong value) {
 			_value = value;
 		}
 
+		/// <summary>
+		/// Advance to the next <see cref="StreamPosition"/>.
+		/// </summary>
+		/// <returns></returns>
+		public StreamPosition Next() => this + 1;
+
 		/// <inheritdoc />
 		public int CompareTo(StreamPosition other) => _value.CompareTo(other._value);
 

src/EventStore.Client/StreamRevision.cs

@@ -44,6 +44,12 @@ public StreamRevision(ulong value) {
 			_value = value;
 		}
 
+		/// <summary>
+		/// Advances the <see cref="StreamRevision"/> to the next revision.
+		/// </summary>
+		/// <returns></returns>
+		public StreamRevision Next() => this + 1;
+
 		/// <inheritdoc />
 		public int CompareTo(StreamRevision other) => _value.CompareTo(other._value);
 

test/EventStore.Client.Tests/StreamPositionTests.cs

@@ -35,6 +35,12 @@ public void AdditionOperator() {
 			Assert.Equal(new StreamPosition(1), 1 + sut);
 		}
 
+		[Fact]
+		public void NextReturnsExpectedResult() {
+			var sut = StreamPosition.Start;
+			Assert.Equal(sut + 1, sut.Next());
+		}
+
 		public static IEnumerable<object[]> AdditionOutOfBoundsCases() {
 			yield return new object[] {StreamPosition.End, 1};
 			yield return new object[] {new StreamPosition(long.MaxValue), long.MaxValue + 2UL};
@@ -59,9 +65,9 @@ public static IEnumerable<object[]> SubtractionOutOfBoundsCases() {
 		}
 
 		[Theory, MemberData(nameof(SubtractionOutOfBoundsCases))]
-		public void SubtractionOutOfBoundsThrows(StreamPosition StreamPosition, ulong operand) {
-			Assert.Throws<OverflowException>(() => StreamPosition - operand);
-			Assert.Throws<OverflowException>(() => (ulong)StreamPosition - new StreamPosition(operand));
+		public void SubtractionOutOfBoundsThrows(StreamPosition streamPosition, ulong operand) {
+			Assert.Throws<OverflowException>(() => streamPosition - operand);
+			Assert.Throws<OverflowException>(() => (ulong)streamPosition - new StreamPosition(operand));
 		}
 
 		public static IEnumerable<object[]> ArgumentOutOfRangeTestCases() {
@@ -75,6 +81,18 @@ public void ArgumentOutOfRange(ulong value) {
 			Assert.Equal(nameof(value), ex.ParamName);
 		}
 
+		[Fact]
+		public void FromStreamPositionEndThrows() {
+			Assert.Throws<ArgumentOutOfRangeException>(() => StreamRevision.FromStreamPosition(StreamPosition.End));
+		}
+
+		[Fact]
+		public void FromStreamPositionReturnsExpectedResult() {
+			var result = StreamPosition.FromStreamRevision(new StreamRevision(0));
+
+			Assert.Equal(new StreamPosition(0), result);
+		}
+
 		public static IEnumerable<object[]> ComparableTestCases() {
 			yield return new object[] {StreamPosition.Start, StreamPosition.Start, 0};
 			yield return new object[] {StreamPosition.Start, StreamPosition.End, -1};

test/EventStore.Client.Tests/StreamRevisionTests.cs

@@ -35,6 +35,12 @@ public void AdditionOperator() {
 			Assert.Equal(new StreamRevision(1), 1 + sut);
 		}
 
+		[Fact]
+		public void NextReturnsExpectedResult() {
+			var sut = new StreamRevision(0);
+			Assert.Equal(sut + 1, sut.Next());
+		}
+
 		public static IEnumerable<object[]> AdditionOutOfBoundsCases() {
 			yield return new object[] {new StreamRevision(long.MaxValue), long.MaxValue + 2UL};
 		}