I don't quite understand why compiling unit tests using DUB doesn't work.

JSON:

{
  "authors": [
    "alexander"
  ],
  "description": "Array Slicing",
  "license": "proprietary",
  "name": "array_slicing",
  "targetName": "program",
  "targetPath": "bin"
}

Projects structure:

├── bin
├── dub.json
└── source
    └── app.d

Errors:

No source files found in configuration 'library'. Falling back to "dub -b unittest".
Performing "unittest" build using /usr/bin/dmd for x86_64.
array_slicing ~master: building configuration "application"...
Linking...
/usr/bin/ld: /usr/lib64/gcc/x86_64-solus-linux/11/../../../../lib64/crt1.o: в функции «_start»:
/home/build/YPKG/root/glibc/build/glibc.git/csu/../sysdeps/x86_64/start.S:110: неопределённая ссылка на «main»
collect2: ошибка: выполнение ld завершилось с кодом возврата 1
Error: linker exited with status 1
/usr/bin/dmd failed with exit code 1.

On Saturday, 2 April 2022 at 11:53:12 UTC, alexanderzhirov wrote:

Source code?

On Saturday, 2 April 2022 at 13:12:04 UTC, Salih Dincer wrote:

A common example from a textbook

import std.array;

bool binarySearch(T)(T[] input, T value)
{
    while (!input.empty)
    {
        auto i = input.length / 2;
        auto mid = input[i];
        if (mid > value)
            input = input[0 .. i];
        else if (mid < value)
            input = input[i + 1 .. $];
        else
            return true;
    }
    return false;
}

unittest
{
    assert(binarySearch([1, 3, 6, 7, 9, 15], 7));
    assert(!binarySearch([1, 3, 6, 7, 9, 15], 5));
}

On Saturday, 2 April 2022 at 13:31:47 UTC, Alexander Zhirov wrote:

import std.array;

bool binarySearch(T)(T[] input, T value)
{
    while (!input.empty)
    {
        auto i = input.length / 2;
        auto mid = input[i];
        if (mid > value)
            input = input[0 .. i];
        else if (mid < value)
            input = input[i + 1 .. $];
        else
            return true;
    }
    return false;
}

unittest
{
    assert(binarySearch([1, 3, 6, 7, 9, 15], 7));
    assert(!binarySearch([1, 3, 6, 7, 9, 15], 5));
}

is there main()? if isn't it, please add the following line at the end:

void main() {}

On 4/2/22 7:53 AM, alexanderzhirov wrote:

{
   "authors": [
     "alexander"
   ],
   "description": "Array Slicing",
   "license": "proprietary",
   "name": "array_slicing",
   "targetName": "program",
   "targetPath": "bin"
}

├── bin
├── dub.json
└── source
     └── app.d

No source files found in configuration 'library'. Falling back to "dub -b unittest".
Performing "unittest" build using /usr/bin/dmd for x86_64.
array_slicing ~master: building configuration "application"...
Linking...
/usr/bin/ld: /usr/lib64/gcc/x86_64-solus-linux/11/../../../../lib64/crt1.o: в функции «_start»:
/home/build/YPKG/root/glibc/build/glibc.git/csu/../sysdeps/x86_64/start.S:110: неопределённая ссылка на «main»
collect2: ошибка: выполнение ld завершилось с кодом возврата 1
Error: linker exited with status 1
/usr/bin/dmd failed with exit code 1.

So to explain a couple things here:

1. you have a source file called app.d, which means to dub that this is an executable target, not a library.
2. dub test is made for libraries. What it does is add its own test runner and main function. Because it thinks you are trying to test an executable, it defaults to running dub -b unittest which is the same as building an application, but just adds the -unittest flag to the compiler.
3. Your build has no main function, so the linker fails.

Solutions:

1. Add a main() function to your program.
2. Change the name of your source file so it doesn't think this is an application
3. Declare the project is a library via targetType.

Without knowing what you are doing with the build, I'd say likely you should add the main function as suggested by Salih Dincer.

-Steve

On Saturday, 2 April 2022 at 14:35:49 UTC, Salih Dincer wrote:

import std.array;

bool binarySearch(T)(T[] input, T value)
{
    while (!input.empty)
    {
        auto i = input.length / 2;
        auto mid = input[i];
        if (mid > value)
            input = input[0 .. i];
        else if (mid < value)
            input = input[i + 1 .. $];
        else
            return true;
    }
    return false;
}

unittest
{
    assert(binarySearch([1, 3, 6, 7, 9, 15], 7));
    assert(!binarySearch([1, 3, 6, 7, 9, 15], 5));
}

void main() {}

I managed to compile the file itself with this command:

dmd -main -unittest app.d

It was also possible to compile with the addition of the main() function to the project.

In the case of dub, I added entry to the project "buildOptions": ["unittests"] and the file now looks like this:

{
  "authors": [
    "alexander"
  ],
  "description": "Array Slicing",
  "license": "proprietary",
  "name": "array_slicing",
  "targetName": "program",
  "targetPath": "bin",
  "buildOptions": ["unittests"]
}

And when I call dub, I get this message

## Warning for package array_slicing ##

The following compiler flags have been specified in the package description
file. They are handled by DUB and direct use in packages is discouraged.
Alternatively, you can set the DFLAGS environment variable to pass custom flags
to the compiler, or use one of the suggestions below:

unittests: Call DUB with --build=unittest

Performing "debug" build using dmd for x86_64.
array_slicing ~master: building configuration "application"...
Linking...
Running bin/program
1 modules passed unittests

But as you can see, the unit test works. But how do I do all this right?

On Saturday, 2 April 2022 at 11:53:12 UTC, alexanderzhirov wrote:

Have a look here
https://andre2007.github.io/d-tips/dub/application_template/

Kind regards
Andre