Consolidate OneOrMany implementation and its usage.

src/Ardalis.Specification.EntityFrameworkCore/Evaluators/SearchEvaluator.cs

@@ -20,11 +20,9 @@ public IQueryable<T> GetQuery<T>(IQueryable<T> query, ISpecification<T> specific
                 return query.ApplySingleLike(searchExpression);
             }
 
-            if (spec.OneOrManySearchExpressions.Values is List<SearchExpressionInfo<T>> list)
-            {
-                var span = CollectionsMarshal.AsSpan(list);
-                return ApplyLike(query, span);
-            }
+            // The search expressions are already sorted by SearchGroup.
+            var span = CollectionsMarshal.AsSpan(spec.OneOrManySearchExpressions.List);
+            return ApplyLike(query, span);
         }
 
 

src/Ardalis.Specification/Evaluators/SearchMemoryEvaluator.cs

@@ -18,11 +18,8 @@ public IEnumerable<T> Evaluate<T>(IEnumerable<T> query, ISpecification<T> specif
                 return new SpecSingleLikeIterator<T>(query, searchExpression);
             }
 
-            if (spec.OneOrManySearchExpressions.Values is List<SearchExpressionInfo<T>> list)
-            {
-                // The search expressions are already sorted by SearchGroup.
-                return new SpecLikeIterator<T>(query, list);
-            }
+            // The search expressions are already sorted by SearchGroup.
+            return new SpecLikeIterator<T>(query, spec.OneOrManySearchExpressions.List);
         }
 
         return query;

src/Ardalis.Specification/Internals/OneOrMany.cs

@@ -68,6 +68,27 @@ public void AddSorted(T item, IComparer<T> comparer)
         }
     }
 
+    /// <summary>
+    /// Gets the list value stored in the instance.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">Thrown if the value is Empty or Single.</exception>
+    public readonly List<T> List
+    {
+        get
+        {
+            if (_value is List<T> list)
+            {
+                return list;
+            }
+
+            throw new InvalidOperationException("The value is not a list.");
+        }
+    }
+
+    /// <summary>
+    /// Gets the single value stored in the instance.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">Thrown if the value is Empty or Many.</exception>
     public readonly T Single
     {
         get
@@ -81,6 +102,10 @@ public readonly T Single
         }
     }
 
+    /// <summary>
+    /// Gets the single value stored in the instance.
+    /// If the value is Empty or Many, returns null.
+    /// </summary>
     public readonly T? SingleOrDefault
     {
         get

src/Ardalis.Specification/Validators/SearchValidator.cs

@@ -16,11 +16,8 @@ public bool IsValid<T>(T entity, ISpecification<T> specification)
                 return searchExpression.SelectorFunc(entity)?.Like(searchExpression.SearchTerm) ?? false;
             }
 
-            if (spec.OneOrManySearchExpressions.Values is List<SearchExpressionInfo<T>> list)
-            {
-                // The search expressions are already sorted by SearchGroup.
-                return IsValid<T>(entity, list);
-            }
+            // The search expressions are already sorted by SearchGroup.
+            return IsValid(entity, spec.OneOrManySearchExpressions.List);
         }
 
         return true;

tests/Ardalis.Specification.Tests/Internals/OneOrManyTests.cs

@@ -184,6 +184,35 @@ public void AddSorted_DoesNothing_GivenInvalidState()
         value.Should().BeEquivalentTo(new string[] { "foo", "bar" });
     }
 
+    [Fact]
+    public void List_ReturnsList_GivenMultipleItems()
+    {
+        var oneOrMany = new OneOrMany<string>();
+        Accessors.ValueOf(ref oneOrMany) = new List<string> { "foo", "bar" };
+
+        oneOrMany.List.Should().BeOfType<List<string>>();
+        oneOrMany.List.Should().Equal(new List<string> { "foo", "bar" });
+    }
+
+    [Fact]
+    public void List_Throws_GivenEmptyStruct()
+    {
+        var oneOrMany = new OneOrMany<string>();
+
+        var action = () => oneOrMany.List;
+        action.Should().Throw<InvalidOperationException>();
+    }
+
+    [Fact]
+    public void List_Throws_GivenSingleItem()
+    {
+        var oneOrMany = new OneOrMany<string>();
+        Accessors.ValueOf(ref oneOrMany) = "foo";
+
+        var action = () => _ = oneOrMany.List;
+        action.Should().Throw<InvalidOperationException>();
+    }
+
     [Fact]
     public void Single_ReturnsSingleItem_GivenSingleItem()
     {