diff --git a/LiteDB.Tests/Issues/Issue2487_Tests.cs b/LiteDB.Tests/Issues/Issue2487_Tests.cs
new file mode 100644
index 000000000..cc3109f03
--- /dev/null
+++ b/LiteDB.Tests/Issues/Issue2487_Tests.cs
@@ -0,0 +1,45 @@
+using FluentAssertions;
+
+using System.Diagnostics;
+
+using Xunit;
+
+namespace LiteDB.Tests.Issues;
+
+public class Issue2487_tests
+{
+    private class DataClass
+    {
+        [BsonId]
+        public int Id { get; set; }
+
+        public string Foo { get; set; }
+
+        public string Bar { get; set; }
+    }
+
+    [Fact]
+    public void Test_Contains_EmptyStrings()
+    {
+        using var engine = new ConnectionString(":memory:").CreateEngine();
+
+        using var db = new LiteDatabase(engine);
+        var collection = db.GetCollection<DataClass>("data");
+
+        collection.Insert(new DataClass { Foo = "bar", Bar = "abc" });
+        collection.Insert(new DataClass { Foo = " ", Bar = "def" });
+        collection.Insert(new DataClass { Foo = "fo bar", Bar = "def" });
+        collection.Insert(new DataClass { Foo = "", Bar = "def" });
+        collection.Insert(new DataClass { Foo = null, Bar = "def" });
+
+        var containsAction = () => collection.FindOne(x => x.Foo.Contains(" "));
+        containsAction.Should().NotThrow();
+
+        var def = containsAction();
+        def.Should().NotBeNull();
+        def.Bar.Should().Be("def");
+
+        var shouldExecute = () => engine.Query("data", Query.All(Query.Contains("Foo", " ")));
+        shouldExecute.Should().NotThrow();
+    }
+}
\ No newline at end of file
diff --git a/LiteDB.Tests/LiteDB.Tests.csproj b/LiteDB.Tests/LiteDB.Tests.csproj
index 2fe8c4f08..831a78701 100644
--- a/LiteDB.Tests/LiteDB.Tests.csproj
+++ b/LiteDB.Tests/LiteDB.Tests.csproj
@@ -9,6 +9,8 @@
     <NeutralLanguage>en-US</NeutralLanguage>
     <GenerateDocumentationFile>false</GenerateDocumentationFile>
     <NoWarn>1701;1702;1705;1591;0618</NoWarn>
+    <SignAssembly>True</SignAssembly>
+    <AssemblyOriginatorKeyFile>..\LiteDB\LiteDB.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/LiteDB/Client/Structures/Query.cs b/LiteDB/Client/Structures/Query.cs
index 28fd6a70f..9bbd6388e 100644
--- a/LiteDB/Client/Structures/Query.cs
+++ b/LiteDB/Client/Structures/Query.cs
@@ -1,7 +1,9 @@
 using LiteDB.Engine;
+
 using System;
 using System.Collections.Generic;
 using System.Linq;
+
 using static LiteDB.Constants;
 
 namespace LiteDB
@@ -83,7 +85,6 @@ public static BsonExpression GT(string field, BsonValue value)
             if (field.IsNullOrWhiteSpace()) throw new ArgumentNullException(nameof(field));
 
             return BsonExpression.Create($"{field} > {value ?? BsonValue.Null}");
-
         }
 
         /// <summary>
@@ -123,7 +124,7 @@ public static BsonExpression StartsWith(string field, string value)
         public static BsonExpression Contains(string field, string value)
         {
             if (field.IsNullOrWhiteSpace()) throw new ArgumentNullException(nameof(field));
-            if (value.IsNullOrWhiteSpace()) throw new ArgumentNullException(nameof(value));
+            if (value.IsNullOrEmpty()) throw new ArgumentNullException(nameof(value));
 
             return BsonExpression.Create($"{field} LIKE {(new BsonValue("%" + value + "%"))}");
         }
diff --git a/LiteDB/Utils/Constants.cs b/LiteDB/Utils/Constants.cs
index 91c480f30..93458193d 100644
--- a/LiteDB/Utils/Constants.cs
+++ b/LiteDB/Utils/Constants.cs
@@ -1,11 +1,12 @@
 using LiteDB.Engine;
+
 using System;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Threading;
 
+[assembly: InternalsVisibleTo("LiteDB.Tests, PublicKey=002400000480000094000000060200000024000052534131000400000100010029e66990e22110ce40a7197e37f8f82df3332c399e696df7f27d09e14ee590ac2dda735d4777fe554c427540bde93b14d3d26c04731c963383dcaa18859c8cbcd4a1a9c394d1204f474c2ab6f23a2eaadf81eb8a7a3d3cc73658868b0302163b92a2614ca050ab703be33c3e1d76f55b11f4f87cb73558f3aa69c1ce726d9ee8")]
 #if DEBUG
-[assembly: InternalsVisibleTo("LiteDB.Tests")]
 [assembly: InternalsVisibleTo("ConsoleApp1")]
 #endif
 
@@ -197,4 +198,4 @@ public static void DEBUG(bool conditional, string message = null)
             }
         }
     }
-}
+}
\ No newline at end of file
diff --git a/LiteDB/Utils/Extensions/StringExtensions.cs b/LiteDB/Utils/Extensions/StringExtensions.cs
index eb777da5e..00ed9b54c 100644
--- a/LiteDB/Utils/Extensions/StringExtensions.cs
+++ b/LiteDB/Utils/Extensions/StringExtensions.cs
@@ -1,16 +1,25 @@
 using System;
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 using System.Security.Cryptography;
 using System.Text;
+
 using static LiteDB.Constants;
 
 namespace LiteDB
 {
     internal static class StringExtensions
     {
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool IsNullOrWhiteSpace(this string str)
         {
-            return str == null || str.Trim().Length == 0;
+            return string.IsNullOrWhiteSpace(str);
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool IsNullOrEmpty(this string str)
+        {
+            return string.IsNullOrEmpty(str);
         }
 
         /// <summary>
@@ -28,13 +37,6 @@ public static bool IsWord(this string str)
             return true;
         }
 
-        public static string TrimToNull(this string str)
-        {
-            var v = str.Trim();
-
-            return v.Length == 0 ? null : v;
-        }
-
         public static string Sha1(this string value)
         {
             var data = Encoding.UTF8.GetBytes(value);