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OneOrMany implementation #507

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Merged
merged 3 commits into from
Jun 12, 2025
Merged

OneOrMany implementation #507

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5afa1fd
Improve OneOrMany implementation.
fiseni Jun 12, 2025
6222fbf
Add tests.
fiseni Jun 12, 2025
4912cec
Throw for null comparer.
fiseni Jun 12, 2025
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58 changes: 55 additions & 3 deletions src/Ardalis.Specification/Internals/OneOrMany.cs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
namespace Ardalis.Specification;

internal struct OneOrMany<T>
internal struct OneOrMany<T> where T : class
{
private object? _value;

Expand All @@ -24,8 +24,47 @@ public void Add(T item)
if (_value is T singleValue)
{
_value = new List<T>(2) { singleValue, item };
}
}

public void AddSorted(T item, IComparer<T> comparer)
{
if (_value is null)
{
_value = item;
return;
}

if (comparer is null)
{
throw new ArgumentNullException(nameof(comparer), "Comparer cannot be null.");
}

if (_value is List<T> list)
{
var index = list.FindIndex(x => comparer.Compare(item, x) <= 0);
if (index == -1)
{
list.Add(item);
}
else
{
list.Insert(index, item);
}
return;
}

if (_value is T singleValue)
{
if (comparer.Compare(item, singleValue) <= 0)
{
_value = new List<T>(2) { item, singleValue };
}
else
{
_value = new List<T>(2) { singleValue, item };
}
}
}

public readonly T Single
Expand All @@ -41,6 +80,19 @@ public readonly T Single
}
}

public readonly T? SingleOrDefault
{
get
{
if (_value is T singleValue)
{
return singleValue;
}

return null;
}
}

public readonly IEnumerable<T> Values
{
get
Expand All @@ -50,9 +102,9 @@ public readonly IEnumerable<T> Values
return Enumerable.Empty<T>();
}

if (_value is List<T> tags)
if (_value is List<T> list)
{
return tags;
return list;
}

if (_value is T singleValue)
Expand Down
113 changes: 113 additions & 0 deletions tests/Ardalis.Specification.Tests/Internals/OneOrManyTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -97,6 +97,93 @@ public void Add_DoesNothing_GivenInvalidState()
value.Should().BeEquivalentTo(new string[] { "foo", "bar" });
}

[Fact]
public void AddSorted_CreatesSingleItem_GivenEmptyStruct()
{
var oneOrMany = new OneOrMany<string>();
oneOrMany.AddSorted("foo", Comparer<string>.Default);

var value = Accessors.ValueOf(ref oneOrMany);
value.Should().BeOfType<string>();
value.Should().Be("foo");
}

[Fact]
public void AddSorted_InsertsInPosition_GivenSingleItem()
{
var oneOrMany = new OneOrMany<string>();
Accessors.ValueOf(ref oneOrMany) = "foo";

oneOrMany.AddSorted("bar", Comparer<string>.Default);

var value = Accessors.ValueOf(ref oneOrMany);
value.Should().BeOfType<List<string>>();
value.Should().BeEquivalentTo(new List<string> { "bar", "foo" });
}

[Fact]
public void AddSorted_AddsToTheEnd_GivenSingleItem()
{
var oneOrMany = new OneOrMany<string>();
Accessors.ValueOf(ref oneOrMany) = "bar";

oneOrMany.AddSorted("foo", Comparer<string>.Default);

var value = Accessors.ValueOf(ref oneOrMany);
value.Should().BeOfType<List<string>>();
value.Should().BeEquivalentTo(new List<string> { "bar", "foo" });
}

[Fact]
public void AddSorted_InsertsInPosition_GivenTwoItems()
{
var oneOrMany = new OneOrMany<string>();
Accessors.ValueOf(ref oneOrMany) = new List<string> { "bar", "foo" };

oneOrMany.AddSorted("baz", Comparer<string>.Default);

var value = Accessors.ValueOf(ref oneOrMany);
value.Should().BeOfType<List<string>>();
value.Should().BeEquivalentTo(new List<string> { "bar", "baz", "foo" });
}

[Fact]
public void AddSorted_AddsToTheEnd_GivenTwoItems()
{
var oneOrMany = new OneOrMany<string>();
Accessors.ValueOf(ref oneOrMany) = new List<string> { "bar", "baz" };

oneOrMany.AddSorted("foo", Comparer<string>.Default);

var value = Accessors.ValueOf(ref oneOrMany);
value.Should().BeOfType<List<string>>();
value.Should().BeEquivalentTo(new List<string> { "bar", "baz", "foo" });
}

[Fact]
public void AddSorted_ThrowsArgumentNullException_GivenNullComparer()
{
var oneOrMany = new OneOrMany<string>();
Accessors.ValueOf(ref oneOrMany) = new List<string> { "bar", "baz" };

var action = () => oneOrMany.AddSorted("foo", null!);

action.Should().Throw<ArgumentNullException>();
}

[Fact]
public void AddSorted_DoesNothing_GivenInvalidState()
{
var oneOrMany = new OneOrMany<string>();
Accessors.ValueOf(ref oneOrMany) = new string[] { "foo", "bar" };

oneOrMany.AddSorted("baz", Comparer<string>.Default);

var value = Accessors.ValueOf(ref oneOrMany);
value.Should().BeOfType<string[]>();
value.Should().BeEquivalentTo(new string[] { "foo", "bar" });
}

[Fact]
public void Single_ReturnsSingleItem_GivenSingleItem()
{
Expand Down Expand Up @@ -125,6 +212,32 @@ public void Single_Throws_GivenMultipleItems()
action.Should().Throw<InvalidOperationException>();
}

[Fact]
public void SingleOrDefault_ReturnsSingleItem_GivenSingleItem()
{
var oneOrMany = new OneOrMany<string>();
Accessors.ValueOf(ref oneOrMany) = "foo";

oneOrMany.SingleOrDefault.Should().Be("foo");
}

[Fact]
public void SingleOrDefault_ReturnsDefault_GivenEmptyStruct()
{
var oneOrMany = new OneOrMany<string>();

oneOrMany.SingleOrDefault.Should().BeNull();
}

[Fact]
public void SingleOrDefault_ReturnsDefault_GivenMultipleItems()
{
var oneOrMany = new OneOrMany<string>();
Accessors.ValueOf(ref oneOrMany) = new string[] { "foo", "bar" };

oneOrMany.SingleOrDefault.Should().BeNull();
}

[Fact]
public void Values_ReturnsEmpty_GivenEmptyStruct()
{
Expand Down