Break MaxMagnitude and MinMagnitude ties by sign, as int and double do

PreciseNumber.Test/PreciseNumberTests.cs

@@ -608,7 +608,7 @@ public void TestStaticMinMagnitude()
 		PreciseNumber one = PreciseNumber.One;
 		PreciseNumber negativeOne = PreciseNumber.NegativeOne;
 		PreciseNumber result = PreciseNumber.MinMagnitude(one, negativeOne);
-		Assert.AreEqual(one, result);
+		Assert.AreEqual(negativeOne, result);
 	}
 
 	[TestMethod]
@@ -617,7 +617,35 @@ public void TestStaticMinMagnitudeNumber()
 		PreciseNumber one = PreciseNumber.One;
 		PreciseNumber negativeOne = PreciseNumber.NegativeOne;
 		PreciseNumber result = PreciseNumber.MinMagnitudeNumber(one, negativeOne);
-		Assert.AreEqual(one, result);
+		Assert.AreEqual(negativeOne, result);
+	}
+
+	[TestMethod]
+	[DataRow(-2, 2)]
+	[DataRow(2, -2)]
+	public void TestMagnitudeTiesFollowInt(int x, int y)
+	{
+		PreciseNumber px = x.ToPreciseNumber();
+		PreciseNumber py = y.ToPreciseNumber();
+
+		Assert.AreEqual(int.MaxMagnitude(x, y).ToPreciseNumber(), PreciseNumber.MaxMagnitude(px, py));
+		Assert.AreEqual(int.MaxMagnitude(x, y).ToPreciseNumber(), PreciseNumber.MaxMagnitudeNumber(px, py));
+		Assert.AreEqual(int.MinMagnitude(x, y).ToPreciseNumber(), PreciseNumber.MinMagnitude(px, py));
+		Assert.AreEqual(int.MinMagnitude(x, y).ToPreciseNumber(), PreciseNumber.MinMagnitudeNumber(px, py));
+	}
+
+	[TestMethod]
+	[DataRow(-3, 2)]
+	[DataRow(2, -3)]
+	[DataRow(3, -2)]
+	[DataRow(-2, 3)]
+	public void TestMagnitudeWithoutATiePicksByAbsoluteValue(int x, int y)
+	{
+		PreciseNumber px = x.ToPreciseNumber();
+		PreciseNumber py = y.ToPreciseNumber();
+
+		Assert.AreEqual(int.MaxMagnitude(x, y).ToPreciseNumber(), PreciseNumber.MaxMagnitude(px, py));
+		Assert.AreEqual(int.MinMagnitude(x, y).ToPreciseNumber(), PreciseNumber.MinMagnitude(px, py));
 	}
 
 	[TestMethod]

PreciseNumber/PreciseNumber.cs

@@ -697,7 +697,7 @@
 	/// A fixed precision such as <c>E15</c> rounds values that need 17 digits, which turns
 	/// <see cref="double.MaxValue"/> into a number that converts back to infinity.
 	/// </remarks>
 	internal static string GetStringFormatForFloatType<TFloat>()
 		where TFloat : INumber<TFloat>
 		=> "R";
 
@@ -1097,21 +1097,43 @@
 		value.Significand == 0;
 
 	/// <inheritdoc/>
-	public static PreciseNumber MaxMagnitude(PreciseNumber x, PreciseNumber y) =>
-		x.Abs() >= y.Abs() ? x : y;
+	/// <remarks>
+	/// When the magnitudes are equal, the positive value is returned, as for <see cref="int"/> and <see cref="double"/>.
+	/// </remarks>
+	public static PreciseNumber MaxMagnitude(PreciseNumber x, PreciseNumber y)
+	{
+		int comparison = x.Abs().CompareTo(y.Abs());
+		if (comparison != 0)
+		{
+			return comparison > 0 ? x : y;
+		}
+
+		return IsNegative(x) ? y : x;
+	}
 
 	/// <inheritdoc/>
 	public static PreciseNumber MaxMagnitudeNumber(PreciseNumber x, PreciseNumber y) => MaxMagnitude(x, y);
 
 	/// <inheritdoc/>
-	public static PreciseNumber MinMagnitude(PreciseNumber x, PreciseNumber y) =>
-		x.Abs() <= y.Abs() ? x : y;
+	/// <remarks>
+	/// When the magnitudes are equal, the negative value is returned, as for <see cref="int"/> and <see cref="double"/>.
+	/// </remarks>
+	public static PreciseNumber MinMagnitude(PreciseNumber x, PreciseNumber y)
+	{
+		int comparison = x.Abs().CompareTo(y.Abs());
+		if (comparison != 0)
+		{
+			return comparison < 0 ? x : y;
+		}
+
+		return IsNegative(x) ? x : y;
+	}
 
 	/// <inheritdoc/>
 	public static PreciseNumber MinMagnitudeNumber(PreciseNumber x, PreciseNumber y) => MinMagnitude(x, y);
 
 	/// <inheritdoc/>
 	public static PreciseNumber Parse(ReadOnlySpan<char> s, NumberStyles style, IFormatProvider? provider)
 	{
 		if (s.IsEmpty)
 		{