Introduce substitute refactoring comes to NSubstitute.Analyzers

2020-04-092020-04-12 TPodolakNSubstitute.Analyzers

I am glad to announce the newest version of NSubstitute.Analyzers comes with “introduce substitute” refactoring, which allows you to automatically create substitutes for constructor arguments as fields or local variables. As an image is worth a thousand words here is a quick demo of C# version

and VisualBasic one

Performance improvements in NSubstitute.Analyzers 1.0.11

2019-10-21 TPodolakNSubstitute, NSubstitute.Analyzers, Roslyn

1. Introduction

I am glad to announce that the latest release of NSubstitute.Analyzers (apart from some bugfixes) brings a lot of performance and memory usage improvements for most of the analyzers. The benchmark results shown below should give you enough information about the speed and memory consumption of the newest version of the library. If you are interested in actual changes behind these results please take a look at this pull request.

2. Benchmark comparision of NSubstitute.Analyzers.CSharp

Analyzer	Mean (us)	Error (us)	StdDev (us)	Gen 0	Gen 1	Allocated (KB)
CallInfoAnalyzer	1,897.0	5.646	5.2814	136.7188	11.7188	424.54
ConflictingArgumentAssignmentsAnalyzer	554.2	1.018	0.9524	33.2031	1.9531	103.47
NonSubstitutableMemberAnalyzer	2,466.9	9.317	8.2596	179.6875	15.6250	560.33
NonSubstitutableMemberReceivedAnalyzer	644.4	2.280	1.9039	31.2500	6.8359	96.27
NonSubstitutableMemberWhenAnalyzer	995.9	2.320	1.9370	37.1094	7.8125	116.74
ReEntrantSetupAnalyzer	57,979.0	196.824	174.4794	2333.3333	–	7175.61
SubstituteAnalyzer	1,960.4	8.197	7.2666	89.8438	19.5313	343.67
UnusedReceivedAnalyzer	524.0	1.671	1.5630	29.2969	1.9531	92.45

Benchmark results of NSubstitute.Analyzers.CSharp 1.0.11
Analyzer	Mean (us)	Error (us)	StdDev (us)	Gen 0	Gen 1	Allocated (KB)
CallInfoAnalyzer	1,828.8	5.599	4.963	123.0469	11.7188	379.78
ConflictingArgumentAssignmentsAnalyzer	510.3	1.973	1.846	33.2031	1.9531	102.76
NonSubstitutableMemberAnalyzer	766.0	2.798	2.336	39.0625	8.7891	122.27
NonSubstitutableMemberReceivedAnalyzer	600.6	3.411	3.191	27.3438	5.8594	85.82
NonSubstitutableMemberWhenAnalyzer	866.0	3.144	2.941	34.1797	9.7656	107.87
ReEntrantSetupAnalyzer	7,442.0	34.067	31.866	281.2500	15.6250	870.18
SubstituteAnalyzer	1,870.2	29.787	27.863	87.8906	23.4375	346.09
UnusedReceivedAnalyzer	482.1	1.705	1.511	25.8789	1.9531	80.96

3. Benchmark comparision of NSubstitute.Analyzers.VisualBasic

Method	Mean (ms)	Error (ms)	StdDev (ms)	Gen 0	Gen 1	Allocated (KB)
CallInfoAnalyzer	3.459	0.0137	0.0121	156.2500	11.7188	484.15
ConflictingArgumentAssignmentsAnalyzer	1.279	0.0103	0.0086	21.4844	1.9531	69.15
NonSubstitutableMemberAnalyzer	1.975	0.0108	0.0090	35.1563	7.8125	108
NonSubstitutableMemberReceivedAnalyzer	1.287	0.0070	0.0065	13.6719	1.9531	47.46
NonSubstitutableMemberWhenAnalyzer	1.589	0.0103	0.0092	25.3906	5.8594	82.72
ReEntrantSetupAnalyzer	54.131	0.2320	0.1937	3600.0000	–	11139.45
SubstituteAnalyzer	3.615	0.0168	0.0149	105.4688	23.4375	393.13
UnusedReceivedAnalyzer	1.306	0.0258	0.0528	13.6719	1.9531	43.3

Benchmark results of NSubstitute.Analyzers.VisualBasic
1.0.11
Analyzer	Mean (ms)	Error (ms)	StdDev (ms)	Gen 0	Gen 1	Allocated (KB)
CallInfoAnalyzer	3.737	0.0878	0.1110	152.3438	11.7188	471.79
ConflictingArgumentAssignmentsAnalyzer	1.402	0.0266	0.0285	21.4844	1.9531	68.36
NonSubstitutableMemberAnalyzer	1.543	0.0264	0.0247	25.3906	5.8594	81
NonSubstitutableMemberReceivedAnalyzer	1.213	0.0051	0.0048	13.6719	1.9531	45.43
NonSubstitutableMemberWhenAnalyzer	1.475	0.0055	0.0051	27.3438	7.8125	85.25
ReEntrantSetupAnalyzer	7.044	0.0236	0.0209	265.6250	7.8125	837.14
SubstituteAnalyzer	3.333	0.0912	0.1186	101.5625	23.4375	377.16
UnusedReceivedAnalyzer	1.102	0.0067	0.0062	11.7188	–	40.24

NSubstitute – returning value from IEnumerable

2017-06-122017-06-14 TPodolakNSubstitute

I’ve been using NSubstitute combined with automocks for quite some time already, but recently I’ve encountered quite interesting situation. Let’s assume that we have the following class we need to write tests for

public class PriceValidator : IValidator<Price>
{
    private readonly IEnumerable<IValidator<Price>> _innerValidators;

    public PriceValidator(IEnumerable<IValidator<Price>> innerValidators)
    {
         _innerValidators = innerValidators;
    }

    public bool IsValid(Price input)
    {
        return _innerValidators.Any() && _innerValidators.All(validator => validator.IsValid(input));
    }
}

public class PriceValidator : IValidator<Price>

{

private readonly IEnumerable<IValidator<Price>> _innerValidators;

public PriceValidator(IEnumerable<IValidator<Price>> innerValidators)

{

_innerValidators = innerValidators;

}

public bool IsValid(Price input)

{

return _innerValidators.Any() && _innerValidators.All(validator => validator.IsValid(input));

}

As mentioned before I wanted to test that class leveraging the concept of automocks. If you have never used them before, no worries, the idea is pretty simple. Instead of providing mock dependencies manually, you just generate them automatically. Once the dependencies are mocked you can retrieve and set them up if necessary. So in my case, I have to setup IEnumerable<IValidator<Price>> mock so that it yields some values. It can be achieved by mocking return values of GetEnumerator() method.

var automock = new NSubstituteAutoMocker<PriceValidator>();
var innerValidators = new List<IValidator<Price>>
{
    Substitute.For<IValidator<Price>>(),
};            
automock.Get<IEnumerable<IValidator<Price>>>().GetEnumerator().Returns(innerValidators.GetEnumerator());

var automock = new NSubstituteAutoMocker<PriceValidator>();

var innerValidators = new List<IValidator<Price>>

{

Substitute.For<IValidator<Price>>(),

};

automock.Get<IEnumerable<IValidator<Price>>>().GetEnumerator().Returns(innerValidators.GetEnumerator());

The entire test then can be written as

[Fact]
public void IsValid_ReturnsTrue_WhenAllInnerValidatorsAreValid()
{
    var automock = new NSubstituteAutoMocker<PriceValidator>();
    var innerValidators = new List<IValidator<Price>>
    {
        Substitute.For<IValidator<Price>>(),
    };
    innerValidators.ForEach(validator => validator.IsValid(Arg.Any<Price>()).Returns(true));
    automock.Get<IEnumerable<IValidator<Price>>>().GetEnumerator().Returns(innerValidators.GetEnumerator());
            
    var result = automock.ClassUnderTest.IsValid(new Price());

    innerValidators.ForEach(validator => validator.Received(1).IsValid(Arg.Any<Price>()));
    result.Should().BeTrue();
}

[Fact]

public void IsValid_ReturnsTrue_WhenAllInnerValidatorsAreValid()

{

var automock = new NSubstituteAutoMocker<PriceValidator>();

var innerValidators = new List<IValidator<Price>>

{

Substitute.For<IValidator<Price>>(),

};

innerValidators.ForEach(validator => validator.IsValid(Arg.Any<Price>()).Returns(true));

automock.Get<IEnumerable<IValidator<Price>>>().GetEnumerator().Returns(innerValidators.GetEnumerator());

var result = automock.ClassUnderTest.IsValid(new Price());

innerValidators.ForEach(validator => validator.Received(1).IsValid(Arg.Any<Price>()));

result.Should().BeTrue();

}

Everything looks good at that point, however if you run the tests, it will fail

That was quite surprising for me and I have to admit that at the beginning I thought it was a bug in NSubstitute.
However, if you looks closely at the implementation of the test, you will see that every time validator collection is enumerated, the same instance of the enumerator is used. As the enumerator keeps its state, the first enumeration (_innerValidators.Any()) will move a current element to the first position (which is the last position at the same time) so when I try to enumerate again (_innerValidators.All(validator => validator.IsValid(input)) enumeration will continue from the previous position and the iteration will end yielding no results. Fortunately, with NSubstitute you can configure the call so that it always returns a new value. The relevant code changes are shown below

automock.Get<IEnumerable<IValidator<Price>>>().GetEnumerator().Returns(callInfo => innerValidators.GetEnumerator());

1	automock.Get<IEnumerable<IValidator<Price>>>().GetEnumerator().Returns(callInfo => innerValidators.GetEnumerator());

Running the tests again will give us “green” result

Source code for this post can be found here

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