[feature] Make self.dependencies available for test_package

When creating a test package for a Conan tool package, there are few ways to validate its package. One way checking its output, like its version and comparing from the package:

def test(self)
    output = io.StringIO()
    self.run("foo --version", env="conanrun", output=output)
    current_version = str(output.getvalue())
    require_version = str(self.deps_cpp_info["foo"].version)
    assert required_version == current_version

In case we try to use self.dependencies["foo"], it returns None.

• I’ve read the CONTRIBUTING guide.

[franramirez688]

Hi @uilianries!

I think this issue is duplicated. Have a look at https://github.com/conan-io/docs/issues/2794

[uilianries]

Closing this one as it’s duplicated with https://github.com/conan-io/docs/issues/2794