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merged 3 commits into from
Oct 18, 2025
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feat(assertions): Source generate IsEqualTo extension methods #3434

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c6dc196
feat(assertions): Source generate IsEqualTo extension methods
thomhurst Oct 17, 2025
0d257e7
refactor(assertions): rename IsEqualTo methods to IsEquatableTo for c…
thomhurst Oct 17, 2025
f3f8032
fix(assertions): simplify assertion messages by removing redundant "e…
thomhurst Oct 18, 2025
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19 changes: 16 additions & 3 deletions TUnit.Assertions.SourceGenerator/Generators/AssertionExtensionGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -59,14 +59,19 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
return null;
}

// Extract optional negated method name
// Extract optional negated method name and overload resolution priority
string? negatedMethodName = null;
int overloadPriority = 0; // Default to 0
foreach (var namedArg in attributeData.NamedArguments)
{
if (namedArg.Key == "NegatedMethodName")
{
negatedMethodName = namedArg.Value.Value?.ToString();
}
else if (namedArg.Key == "OverloadResolutionPriority" && namedArg.Value.Value is int priority)
{
overloadPriority = priority;
}
}

// Find the base Assertion<T> type to extract the type parameter
Expand All @@ -92,7 +97,8 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
methodName!,
negatedMethodName,
assertionBaseType,
constructors
constructors,
overloadPriority
);
}

Expand Down Expand Up @@ -288,6 +294,12 @@ private static void GenerateExtensionMethod(
sourceBuilder.AppendLine($" /// Extension method for {assertionType.Name}.");
sourceBuilder.AppendLine(" /// </summary>");

// Add OverloadResolutionPriority attribute only if priority > 0
if (data.OverloadResolutionPriority > 0)
{
sourceBuilder.AppendLine($" [global::System.Runtime.CompilerServices.OverloadResolutionPriority({data.OverloadResolutionPriority})]");
}

// Method declaration
var returnType = assertionType.IsGenericType
? $"{assertionType.Name}{genericParamsString}"
Expand Down Expand Up @@ -393,6 +405,7 @@ private record AssertionExtensionData(
string MethodName,
string? NegatedMethodName,
INamedTypeSymbol AssertionBaseType,
ImmutableArray<IMethodSymbol> Constructors
ImmutableArray<IMethodSymbol> Constructors,
int OverloadResolutionPriority
);
}
4 changes: 2 additions & 2 deletions TUnit.Assertions.Tests/AssertMultipleTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ await Assert.That(async () =>

await Assert.That(3).IsEqualTo(6);
}
}).Throws<Exception>().And.HasMessageContaining("Expected to be equal to 2");
}).Throws<Exception>().And.HasMessageContaining("Expected to be 2");
}

[Test]
Expand Down Expand Up @@ -51,7 +51,7 @@ public async Task Caught_Exception_In_Scope_Is_Not_Captured()
}).Throws<Exception>();

await Assert.That(exception!.Message)
.Contains("Expected to be equal to 2");
.Contains("Expected to be 2");
}

[Test]
Expand Down
32 changes: 16 additions & 16 deletions TUnit.Assertions.Tests/EquatableTests.cs
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Expand Up @@ -76,7 +76,7 @@ public async Task Wrapper_IsEqualTo_Long_Success()
Wrapper wrapper = new() { Value = 42 };

// Act & Assert
await Assert.That(wrapper).IsEqualTo(42L);
await Assert.That(wrapper).IsEquatableTo(42L);
}

[Test]
Expand All @@ -88,7 +88,7 @@ public async Task Wrapper_IsEqualTo_Long_Failure()
// Act & Assert
await Assert.ThrowsAsync<TUnit.Assertions.Exceptions.AssertionException>(async () =>
{
await Assert.That(wrapper).IsEqualTo(99L);
await Assert.That(wrapper).IsEquatableTo(99L);
});
}

Expand All @@ -110,7 +110,7 @@ public async Task NullableWrapper_IsEqualTo_Long_Success()
Wrapper? wrapper = new Wrapper { Value = 42 };

// Act & Assert
await Assert.That(wrapper).IsEqualTo(42L);
await Assert.That(wrapper).IsEquatableTo(42L);
}

[Test]
Expand All @@ -122,7 +122,7 @@ public async Task NullableWrapper_IsEqualTo_Long_NullFailure()
// Act & Assert
await Assert.ThrowsAsync<TUnit.Assertions.Exceptions.AssertionException>(async () =>
{
await Assert.That(wrapper).IsEqualTo(42L);
await Assert.That(wrapper).IsEquatableTo(42L);
});
}

Expand All @@ -133,7 +133,7 @@ public async Task MultiEquatable_IsEqualTo_Int_Success()
MultiEquatable value = new() { IntValue = 100, StringValue = "test" };

// Act & Assert
await Assert.That(value).IsEqualTo(100);
await Assert.That(value).IsEquatableTo(100);
}

[Test]
Expand All @@ -143,7 +143,7 @@ public async Task MultiEquatable_IsEqualTo_String_Success()
MultiEquatable value = new() { IntValue = 100, StringValue = "test" };

// Act & Assert
await Assert.That(value).IsEqualTo("test");
await Assert.That(value).IsEquatableTo("test");
}

[Test]
Expand All @@ -153,7 +153,7 @@ public async Task IntWrapper_IsEqualTo_Int_Success()
IntWrapper wrapper = new() { Value = 123 };

// Act & Assert
await Assert.That(wrapper).IsEqualTo(123);
await Assert.That(wrapper).IsEquatableTo(123);
}

[Test]
Expand All @@ -165,7 +165,7 @@ public async Task IntWrapper_IsEqualTo_Int_Failure()
// Act & Assert
await Assert.ThrowsAsync<TUnit.Assertions.Exceptions.AssertionException>(async () =>
{
await Assert.That(wrapper).IsEqualTo(456);
await Assert.That(wrapper).IsEquatableTo(456);
});
}

Expand All @@ -176,7 +176,7 @@ public async Task EquatableAssertion_WithAnd_Success()
Wrapper wrapper = new() { Value = 42 };

// Act & Assert
await Assert.That(wrapper).IsEqualTo(42L).And.IsEqualTo(new Wrapper { Value = 42 });
await Assert.That(wrapper).IsEquatableTo(42L).And.IsEqualTo(new Wrapper { Value = 42 });
}

[Test]
Expand All @@ -186,7 +186,7 @@ public async Task EquatableAssertion_WithOr_Success()
Wrapper wrapper = new() { Value = 42 };

// Act & Assert - should pass because first condition is true
await Assert.That(wrapper).IsEqualTo(42L).Or.IsEqualTo(new Wrapper { Value = 99 });
await Assert.That(wrapper).IsEquatableTo(42L).Or.IsEqualTo(new Wrapper { Value = 99 });
}

[Test]
Expand All @@ -198,7 +198,7 @@ public async Task EquatableAssertion_WithAnd_Failure()
// Act & Assert
await Assert.ThrowsAsync<TUnit.Assertions.Exceptions.AssertionException>(async () =>
{
await Assert.That(wrapper).IsEqualTo(42L).And.IsEqualTo(new Wrapper { Value = 99 });
await Assert.That(wrapper).IsEquatableTo(42L).And.IsEqualTo(new Wrapper { Value = 99 });
});
}

Expand All @@ -209,7 +209,7 @@ public async Task EquatableAssertion_ChainedWithAndContinuation()
Wrapper wrapper = new() { Value = 42 };

// Act & Assert - test that And continuation works
await Assert.That(wrapper).IsEqualTo(42L).And.IsEqualTo(42L);
await Assert.That(wrapper).IsEquatableTo(42L).And.IsEquatableTo(42L);
}

[Test]
Expand All @@ -219,7 +219,7 @@ public async Task EquatableAssertion_ChainedWithOrContinuation()
Wrapper wrapper = new() { Value = 42 };

// Act & Assert - test that Or continuation works
await Assert.That(wrapper).IsEqualTo(99L).Or.IsEqualTo(42L);
await Assert.That(wrapper).IsEquatableTo(99L).Or.IsEquatableTo(42L);
}

[Test]
Expand All @@ -229,7 +229,7 @@ public async Task NullableIntWrapper_IsEqualTo_Int_Success()
IntWrapper? wrapper = new IntWrapper { Value = 789 };

// Act & Assert
await Assert.That(wrapper).IsEqualTo(789);
await Assert.That(wrapper).IsEquatableTo(789);
}

[Test]
Expand All @@ -241,7 +241,7 @@ public async Task NullableIntWrapper_IsEqualTo_Int_NullFailure()
// Act & Assert
await Assert.ThrowsAsync<TUnit.Assertions.Exceptions.AssertionException>(async () =>
{
await Assert.That(wrapper).IsEqualTo(789);
await Assert.That(wrapper).IsEquatableTo(789);
});
}

Expand All @@ -262,7 +262,7 @@ public async Task GitHubIssue2972_Example()
{
// This is the exact example from the GitHub issue
Wrapper value = new() { Value = 1 };
await Assert.That(value).IsEqualTo(1L);
await Assert.That(value).IsEquatableTo(1L);
}
}
#endif
44 changes: 22 additions & 22 deletions TUnit.Assertions.Tests/Old/AssertMultipleTests.cs
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Expand Up @@ -29,35 +29,35 @@ public async Task MultipleFailures()
var exception5 = (TUnitAssertionException) aggregateException.InnerExceptions[4];

await TUnitAssert.That(exception1.Message).IsEqualTo("""
Expected to be equal to 2
Expected to be 2
but found 1

at Assert.That(1).IsEqualTo(2)
""");

await TUnitAssert.That(exception2.Message).IsEqualTo("""
Expected to be equal to 3
Expected to be 3
but found 2

at Assert.That(2).IsEqualTo(3)
""");

await TUnitAssert.That(exception3.Message).IsEqualTo("""
Expected to be equal to 4
Expected to be 4
but found 3

at Assert.That(3).IsEqualTo(4)
""");

await TUnitAssert.That(exception4.Message).IsEqualTo("""
Expected to be equal to 5
Expected to be 5
but found 4

at Assert.That(4).IsEqualTo(5)
""");

await TUnitAssert.That(exception5.Message).IsEqualTo("""
Expected to be equal to 6
Expected to be 6
but found 5

at Assert.That(5).IsEqualTo(6)
Expand Down Expand Up @@ -88,40 +88,40 @@ public async Task MultipleFailures_With_Connectors()
var exception5 = (TUnitAssertionException) aggregateException.InnerExceptions[4];

await TUnitAssert.That(exception1.Message).IsEqualTo("""
Expected to be equal to 2
or to be equal to 3
Expected to be 2
or to be 3
but found 1

at Assert.That(1).IsEqualTo(2).Or.IsEqualTo(3)
""");

await TUnitAssert.That(exception2.Message).IsEqualTo("""
Expected to be equal to 3
and to be equal to 4
Expected to be 3
and to be 4
but found 2

at Assert.That(2).IsEqualTo(3).And.IsEqualTo(4)
""");

await TUnitAssert.That(exception3.Message).IsEqualTo("""
Expected to be equal to 4
or to be equal to 5
Expected to be 4
or to be 5
but found 3

at Assert.That(3).IsEqualTo(4).Or.IsEqualTo(5)
""");

await TUnitAssert.That(exception4.Message).IsEqualTo("""
Expected to be equal to 5
and to be equal to 6
Expected to be 5
and to be 6
but found 4

at Assert.That(4).IsEqualTo(5).And.IsEqualTo(6)
""");

await TUnitAssert.That(exception5.Message).IsEqualTo("""
Expected to be equal to 6
or to be equal to 7
Expected to be 6
or to be 7
but found 5

at Assert.That(5).IsEqualTo(6).Or.IsEqualTo(7)
Expand Down Expand Up @@ -172,49 +172,49 @@ public async Task Nested_Multiples()
var assertionException7 = (TUnitAssertionException) aggregateException.InnerExceptions[6];

await TUnitAssert.That(assertionException1.Message).IsEqualTo("""
Expected to be equal to 2
Expected to be 2
but found 1

at Assert.That(1).IsEqualTo(2)
""");

await TUnitAssert.That(assertionException2.Message).IsEqualTo("""
Expected to be equal to 3
Expected to be 3
but found 2

at Assert.That(2).IsEqualTo(3)
""");

await TUnitAssert.That(assertionException3.Message).IsEqualTo("""
Expected to be equal to 4
Expected to be 4
but found 3

at Assert.That(3).IsEqualTo(4)
""");

await TUnitAssert.That(assertionException4.Message).IsEqualTo("""
Expected to be equal to 5
Expected to be 5
but found 4

at Assert.That(4).IsEqualTo(5)
""");

await TUnitAssert.That(assertionException5.Message).IsEqualTo("""
Expected to be equal to 6
Expected to be 6
but found 5

at Assert.That(5).IsEqualTo(6)
""");

await TUnitAssert.That(assertionException6.Message).IsEqualTo("""
Expected to be equal to 7
Expected to be 7
but found 6

at Assert.That(6).IsEqualTo(7)
""");

await TUnitAssert.That(assertionException7.Message).IsEqualTo("""
Expected to be equal to 8
Expected to be 8
but found 7

at Assert.That(7).IsEqualTo(8)
Expand Down
6 changes: 3 additions & 3 deletions TUnit.Assertions.Tests/Old/EqualityComparerTests.cs
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Expand Up @@ -19,15 +19,15 @@ public async Task ComparerTestFailureAsync()
{
const double a = 10;
const double b = 0;
// Old API used to accept IEqualityComparer, new API requires using the comparer directly
await TUnitAssert.That(new Comparer().Equals(a, b)).IsTrue();
// With IEqualityComparer support restored, we can use it directly
await TUnitAssert.That(a).IsEqualTo(b, new Comparer());
}

[Test]
public async Task ComparerTestSuccessAsync()
{
const double a = 10;
const double b = 0;
await TUnitAssert.That(new Comparer().Equals(a, b)).IsTrue();
await TUnitAssert.That(a).IsEqualTo(b, new Comparer());
}
}
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