[mdatagen]: provide mutualised assertions template

[mmorel-35]

After having done some evolution on mdatagen related with the best practices of testify I’d like to suggest the use of a common function to generate code assertions. It used to be a simple assert.Equal(t, ..., ...) But it’s better to have

• assert.(True|False)(t, ...) for boolean
• assert.InDelta(t, ..., ..., precision) for double
• assert.Equal(t, ..., ...) for the other types

This code has to be replicated in several places. It would be nice defining a reusable template so in case of evolution it will be easier to evolve.

[mmorel-35]

cc @jade-guiton-dd, @mx-psi , @codeboten, @bogdandrutu ,

Related to

• https://github.com/open-telemetry/opentelemetry-collector/pull/11149
• https://github.com/open-telemetry/opentelemetry-collector/pull/11169
• https://github.com/open-telemetry/opentelemetry-collector/pull/11136