Issue4413 caller argument expression

[manfred-brands]

@OsirisTerje I see a problem, the compiler cannot distinguish between:

Assert.That(actual, constraint, [CAE] string actualExpression =  "", [CAE] string constraintExpression =  "")
{}
Assert.That(actual, constraint, string? message, [CAE] string actualExpression =  "", [CAE] string constraintExpression = "")
{}

When calling it like:

Assert.That(actual, constraint, message)

Because it matches both.

[manfred-brands]

See here:

It thinks we passed an actualMessage not a message.

[OsirisTerje]

Got the same. I changed the nullable message strings into non-null. That sølvet it. Suggest you merge my cae branch into your. I can merge back again tomorrow to get your changes in.

[OsirisTerje]

@manfred-brands Partially merged this into the CallerArgumentExpression branch, PR #4427

We should handle conditional formatting as an addition afterwards. I am not sure why we actually need it btw, but perhaps some discussion I have missed?

There are no overloads that don't compile now.

[manfred-brands]

We should handle conditional formatting as an addition afterwards. I am not sure why we actually need it btw, but perhaps some discussion I have missed?

String formatting is a very expensive operation. Doing this for every unit tests will make tests run much slower.
I created a benchmark test quantifying this, comparing 3 cases:

• NUnit3's: format and params arguments: UseFormatAndArguments
• NUnit4's: string using $"" syntax: UsePreformattedMessage
• PRs: FormattableString using $"" syntax: UseFormattableMessage

On tests that never fail, the pre-formatted option is 6x slower (net7.0) or even 22x slower (net48).
The FormattableString is still 2x slower than the message and arguments, because it needs to allocate the FormattableString instance.
I don't know what in real world the amount of tests is that pass in extra arguments.
From our main applications 209978 Assert calls only 445 use a format string ({0}) and 370 use a interpolated string ($"").

|                 Method |            Runtime |       Mean | Ratio | Allocated | Alloc Ratio |
|----------------------- |------------------- |-----------:|------:|----------:|------------:|
|  UseFormatAndArguments |           .NET 7.0 |   4.306 ns |  1.00 |      56 B |        1.00 |
| UsePreformattedMessage |           .NET 7.0 |  26.917 ns |  6.25 |     104 B |        1.86 |
|  UseFormattableMessage |           .NET 7.0 |   9.198 ns |  2.14 |      88 B |        1.57 |
|                        |                    |            |       |           |             |
|  UseFormatAndArguments | .NET Framework 4.8 |   5.954 ns |  1.00 |      56 B |        1.00 |
| UsePreformattedMessage | .NET Framework 4.8 | 134.632 ns | 22.62 |     160 B |        2.86 |
|  UseFormattableMessage | .NET Framework 4.8 |  12.593 ns |  2.12 |      88 B |        1.57 |

AssertPerformance.zip

[manfred-brands]

@OsirisTerje Once I noticed that you removed the overloads with no message parameter, I could finish mine.
Seeing what you did, I fixed the nunit test asserting message contains from 'Is.EqualTo' into 'Does.Contain'.
I added nunit tests to assert that the message contains the actual and constraint expressions.

Note that there is no conditional on nunit462/net6.0. the CAE works for all TargetFrameworks.