Constraint the Abs extension method to ILinearQuantity<TQuantity> (#1607)

- replace the constraint from `IQuantity` to `ILinearQuantity<TQuantity>` - moved the extension from `UnitMath` class to the `LinearQuantityExtensions`

Author: lipchev

UnitsNet.Tests/UnitMathTests.cs

@@ -37,14 +37,6 @@ public void AbsoluteValueOfNegativeReturnsPositive()
  Assert.StrictEqual(-quantity, result);
  }
 
- [Fact]
- public void AbsoluteValueOfNullReferenceThrowsException()
- {
- IQuantity quantity = null!;
-
- Assert.Throws<NullReferenceException>(() => quantity.Abs());
- }
-
  [Fact]
  public void AverageOfEmptySourceThrowsException()
  {

UnitsNet/Extensions/LinearQuantityExtensions.cs

@@ -255,4 +255,29 @@ public static TQuantity Average<TSource, TQuantity, TUnit>(this IEnumerable<TSou
  {
  return source.Select(selector).Average(targetUnit);
  }
+
+ /// <summary>
+ /// Returns the absolute value of the specified quantity.
+ /// </summary>
+ /// <typeparam name="TQuantity">
+ /// The type of the quantity, which must implement <see cref="ILinearQuantity{TSelf}" />.
+ /// </typeparam>
+ /// <param name="value">
+ /// The quantity whose absolute value is to be calculated.
+ /// </param>
+ /// <returns>
+ /// A quantity of type <typeparamref name="TQuantity" /> representing the absolute value of the input quantity.
+ /// </returns>
+ /// <exception cref="NullReferenceException">
+ /// Thrown if the input <paramref name="value" /> is <c>null</c>.
+ /// </exception>
+ public static TQuantity Abs<TQuantity>(this TQuantity value)
+ where TQuantity : ILinearQuantity<TQuantity>
+ {
+#if NET
+ return TQuantity.Create(Math.Abs(value.Value), value.UnitKey);
+#else
+ return value.QuantityInfo.Create(Math.Abs(value.Value), value.UnitKey);
+#endif
+ }
 }

UnitsNet/UnitMath.cs

@@ -10,32 +10,6 @@ namespace UnitsNet
  /// </summary>
  public static class UnitMath
  {
- /// <summary>
- /// Returns the absolute value of the specified quantity.
- /// </summary>
- /// <typeparam name="TQuantity">
- /// The type of the quantity, which must implement <see cref="IQuantity" />.
- /// </typeparam>
- /// <param name="value">
- /// The quantity whose absolute value is to be calculated.
- /// </param>
- /// <returns>
- /// A quantity of type <typeparamref name="TQuantity" /> representing the absolute value of the input quantity.
- /// </returns>
- /// <exception cref="NullReferenceException">
- /// Thrown if the input <paramref name="value" /> is <c>null</c>.
- /// </exception>
- public static TQuantity Abs<TQuantity>(this TQuantity value) where TQuantity : IQuantity
- {
- // TODO see about constraining to IQuantityInstance<TQuantity>
-// #if NET
-// return TQuantity.Create(QuantityValue.Abs(value.Value), value.UnitKey);
-// #else
-// return value.QuantityInfo.Create(QuantityValue.Abs(value.Value), value.UnitKey);
-// #endif
- return (TQuantity)value.QuantityInfo.From(Math.Abs(value.Value), value.UnitKey);
- }
-
  /// <summary>Returns the smaller of two <typeparamref name="TQuantity" /> values.</summary>
  /// <typeparam name="TQuantity">The type of quantities to compare.</typeparam>
  /// <param name="val1">The first of two <typeparamref name="TQuantity" /> values to compare.</param>