diff --git a/tests/Bw.VaultDigest.UnitTests/Bw.VaultDigest.UnitTests.csproj b/tests/Bw.VaultDigest.UnitTests/Bw.VaultDigest.UnitTests.csproj
index fe72d63..b36dd30 100644
--- a/tests/Bw.VaultDigest.UnitTests/Bw.VaultDigest.UnitTests.csproj
+++ b/tests/Bw.VaultDigest.UnitTests/Bw.VaultDigest.UnitTests.csproj
@@ -12,9 +12,9 @@
     <ItemGroup>
         <PackageReference Include="AutoFixture" Version="4.18.1"/>
         <PackageReference Include="AutoFixture.Xunit2" Version="4.18.1"/>
-        <PackageReference Include="FluentAssertions" Version="6.12.0"/>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0"/>
         <PackageReference Include="Moq" Version="4.20.70"/>
+        <PackageReference Include="Shouldly" Version="4.3.0" />
         <PackageReference Include="xunit" Version="2.4.2"/>
         <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
diff --git a/tests/Bw.VaultDigest.UnitTests/GlobalUsings.cs b/tests/Bw.VaultDigest.UnitTests/GlobalUsings.cs
index 74fdc36..32f0767 100644
--- a/tests/Bw.VaultDigest.UnitTests/GlobalUsings.cs
+++ b/tests/Bw.VaultDigest.UnitTests/GlobalUsings.cs
@@ -1,4 +1,4 @@
 global using Xunit;
-global using FluentAssertions;
+global using Shouldly;
 global using Moq;
 global using AutoFixture;
\ No newline at end of file
diff --git a/tests/Bw.VaultDigest.UnitTests/Infrastructure/BwClientTests/GetLoginsTests.cs b/tests/Bw.VaultDigest.UnitTests/Infrastructure/BwClientTests/GetLoginsTests.cs
index 1d9f470..c920a28 100644
--- a/tests/Bw.VaultDigest.UnitTests/Infrastructure/BwClientTests/GetLoginsTests.cs
+++ b/tests/Bw.VaultDigest.UnitTests/Infrastructure/BwClientTests/GetLoginsTests.cs
@@ -149,7 +149,7 @@ public async Task GetLogins_WhenUnauthorized(string password, string sessionToke
         VerifyLoginCalled(keys.ClientId, keys.ClientSecret, Times.Once());
         VerifyUnlockCalled(password, Times.Once());
         VerifyGetLoginsCalled(sessionToken, Times.Once());
-        logins.Should().BeEquivalentTo(items);
+        logins.ShouldBeEquivalentTo(items);
     }
 
     [Theory]
@@ -171,7 +171,7 @@ public async Task GetLogins_WhenLocked(string password, string sessionToken, Lis
         VerifyLoginNotCalled();
         VerifyUnlockCalled(password, Times.Once());
         VerifyGetLoginsCalled(sessionToken, Times.Once());
-        logins.Should().BeEquivalentTo(items);
+        logins.ShouldBeEquivalentTo(items);
     }
 
     [Theory]
@@ -192,9 +192,7 @@ public async Task GetLogins_WhenResultFailed(string password, string sessionToke
         Func<Task> act = () => _bwClientMock.Object.GetItems();
 
         await act
-            .Should()
-            .ThrowAsync<Exception>()
-            .WithMessage("Failed to get logins");
+            .ShouldThrowAsync<Exception>("Failed to get logins");
 
         VerifyLoginNotCalled();
         VerifyUnlockCalled(password, Times.Once());
@@ -215,9 +213,7 @@ public async Task GetLogins_WhenFailedToGetPassword()
         Func<Task> act = () => _bwClientMock.Object.GetItems();
 
         await act
-            .Should()
-            .ThrowAsync<Exception>()
-            .WithMessage("Could not retrieve master password");
+            .ShouldThrowAsync<Exception>("Could not retrieve master password");
 
         VerifyLoginNotCalled();
         VerifyUnlockCalled(It.IsAny<string>(), Times.Never());
@@ -236,9 +232,7 @@ public async Task GetLogins_WhenFailedToGetApiKey()
         Func<Task> act = () => _bwClientMock.Object.GetItems();
 
         await act
-            .Should()
-            .ThrowAsync<Exception>()
-            .WithMessage("Could not retrieve Api Keys to login");
+            .ShouldThrowAsync<Exception>("Could not retrieve Api Keys to login");
 
         VerifyLoginNotCalled();
         VerifyUnlockCalled(It.IsAny<string>(), Times.Never());
@@ -257,9 +251,7 @@ public async Task GetLogins_WhenUnknownStatusReceived()
         Func<Task> act = () => _bwClientMock.Object.GetItems();
 
         await act
-            .Should()
-            .ThrowAsync<Exception>()
-            .WithMessage("Unknown status received");
+            .ShouldThrowAsync<Exception>("Unknown status received");
 
         VerifyLoginNotCalled();
         VerifyUnlockCalled(It.IsAny<string>(), Times.Never());
@@ -291,6 +283,6 @@ public async Task GetLogins_ShouldSyncWhenOutdated(string password, string sessi
             .Verify(c => c.Request<string>(EmptyEnvVars, "sync"), Times.Once());
         VerifyUnlockCalled(password, Times.Once());
         VerifyGetLoginsCalled(sessionToken, Times.Once());
-        logins.Should().BeEquivalentTo(items);
+        logins.ShouldBeEquivalentTo(items);
     }
 }
\ No newline at end of file
diff --git a/tests/Bw.VaultDigest.UnitTests/Infrastructure/BwClientTests/SerializationTests.cs b/tests/Bw.VaultDigest.UnitTests/Infrastructure/BwClientTests/SerializationTests.cs
index b347914..17e3c63 100644
--- a/tests/Bw.VaultDigest.UnitTests/Infrastructure/BwClientTests/SerializationTests.cs
+++ b/tests/Bw.VaultDigest.UnitTests/Infrastructure/BwClientTests/SerializationTests.cs
@@ -194,6 +194,6 @@ public void Deserialize_ValidJson_ReturnsObject()
                            ]
                            """;
         var obj = JsonSerializer.Deserialize<IEnumerable<Item>>(str, BwClient.SerializeOptions);
-        obj.Should().NotBeNull();
+        obj.ShouldNotBeNull();
     }
 }
\ No newline at end of file
diff --git a/tests/Bw.VaultDigest.UnitTests/Infrastructure/LoginsMappingTests.cs b/tests/Bw.VaultDigest.UnitTests/Infrastructure/LoginsMappingTests.cs
index 3ec6908..701a61d 100644
--- a/tests/Bw.VaultDigest.UnitTests/Infrastructure/LoginsMappingTests.cs
+++ b/tests/Bw.VaultDigest.UnitTests/Infrastructure/LoginsMappingTests.cs
@@ -113,8 +113,9 @@ public void LoginMapping_ShouldMapLoginsOnly()
 
         var logins = items.ToLogins(DateTime.Now);
 
-        logins.Should().HaveCount(loginItems.Length);
-        logins.Should().OnlyContain(l => loginItems.Any(li => li.Id == l.Id));
+        logins.Count.ShouldBe(loginItems.Length);
+        logins.ShouldContain(l => loginItems.Any(li => li.Id == l.Id));
+        logins.ShouldNotContain(l => loginItems.All(li => li.Id != l.Id));
     }
 
     private class StrengthCalculationData : TheoryData<Strength, string>
@@ -215,10 +216,10 @@ public void LoginMapping_StrengthCalculation(Strength expectedStrength, string p
 
         var logins = items.ToLogins(_fixture.Create<DateTime>());
 
-        logins.Should().HaveCount(1);
-        logins[0].Id.Should().Be(item.Id);
-        logins[0].Name.Should().Be(item.Name);
-        logins[0].Strength.Should().Be(expectedStrength);
+        logins.Count.ShouldBe(1);
+        logins[0].Id.ShouldBe(item.Id);
+        logins[0].Name.ShouldBe(item.Name);
+        logins[0].Strength.ShouldBe(expectedStrength);
     }
 
     private class AgeCalculationData : TheoryData<Age, DateTime, DateTime>
@@ -256,9 +257,9 @@ public void LoginMapping_AgeCalculation(Age expectedAge, DateTime date, DateTime
 
         var logins = items.ToLogins(now);
 
-        logins.Should().HaveCount(1);
-        logins[0].Id.Should().Be(item.Id);
-        logins[0].Name.Should().Be(item.Name);
-        logins[0].Age.Should().Be(expectedAge);
+        logins.Count.ShouldBe(1);
+        logins[0].Id.ShouldBe(item.Id);
+        logins[0].Name.ShouldBe(item.Name);
+        logins[0].Age.ShouldBe(expectedAge);
     }
 }
\ No newline at end of file
diff --git a/tests/Bw.VaultDigest.UnitTests/Services/DigestServiceTests.cs b/tests/Bw.VaultDigest.UnitTests/Services/DigestServiceTests.cs
index 70e84ae..3a1624d 100644
--- a/tests/Bw.VaultDigest.UnitTests/Services/DigestServiceTests.cs
+++ b/tests/Bw.VaultDigest.UnitTests/Services/DigestServiceTests.cs
@@ -30,12 +30,12 @@ public void ToStrengthSlices_Spec()
         var result =
             logins.ToList().ToStrengthSlices();
 
-        result.Should().HaveCount(5);
-        result.Should().Contain(s => s.FillColor == Colors.Red && s.Value == 5);
-        result.Should().Contain(s => s.FillColor == Colors.Orange && s.Value == 7);
-        result.Should().Contain(s => s.FillColor == Colors.Yellow && s.Value == 9);
-        result.Should().Contain(s => s.FillColor == Colors.LightGreen && s.Value == 12);
-        result.Should().Contain(s => s.FillColor == Colors.Green && s.Value == 15);
+        result.Count.ShouldBe(5);
+        result.ShouldContain(s => s.FillColor == Colors.Red && s.Value == 5);
+        result.ShouldContain(s => s.FillColor == Colors.Orange && s.Value == 7);
+        result.ShouldContain(s => s.FillColor == Colors.Yellow && s.Value == 9);
+        result.ShouldContain(s => s.FillColor == Colors.LightGreen && s.Value == 12);
+        result.ShouldContain(s => s.FillColor == Colors.Green && s.Value == 15);
     }
 
     [Fact]
@@ -51,11 +51,11 @@ public void ToAgesSlices_Spec()
         var result =
             logins.ToList().ToAgeSlices();
 
-        result.Should().HaveCount(5);
-        result.Should().Contain(s => s.FillColor == Colors.Red && s.Value == 5);
-        result.Should().Contain(s => s.FillColor == Colors.Orange && s.Value == 7);
-        result.Should().Contain(s => s.FillColor == Colors.Yellow && s.Value == 9);
-        result.Should().Contain(s => s.FillColor == Colors.LightGreen && s.Value == 12);
-        result.Should().Contain(s => s.FillColor == Colors.Green && s.Value == 15);
+        result.Count.ShouldBe(5);
+        result.ShouldContain(s => s.FillColor == Colors.Red && s.Value == 5);
+        result.ShouldContain(s => s.FillColor == Colors.Orange && s.Value == 7);
+        result.ShouldContain(s => s.FillColor == Colors.Yellow && s.Value == 9);
+        result.ShouldContain(s => s.FillColor == Colors.LightGreen && s.Value == 12);
+        result.ShouldContain(s => s.FillColor == Colors.Green && s.Value == 15);
     }
 }
\ No newline at end of file