Add availabilities to the REST API client

[m-timmermann]

This PR adds the availabilities to the REST API client.

See https://github.com/meplato/store.v3/issues/4041

Beware:

• the delete and upsert request can have some delay (they are getting queued up)

[MCwolek]

The service itself so far looks OK. But the c# project Meplato.Store2 doesn't contain the new service yet.
So the build of the service won't include the new service file. You need to modify the Meplato.Store2.csproj file and add this to the existing ItemGroup element which contains the other files:

<Compile Include="Availabilities\Service.cs" />

Also, no new test cases?

[MCwolek]

LGTM 👍🏽
Tested with small .Net Console App.
✅ Get
✅ Delete
✅ Upsert (OK after method changed to PUT)

[MCwolek]

Suggested change

	HttpMethod.Post,
	HttpMethod.Put,

[MCwolek]

Just a general FYI: Project and Solution are using very old .Net version 😉 .Net 4.7.2. Which is multiple years old and is not supported anymore.
The current LTS of .Net is .Net 8

[MCwolek]

In the older .Net or C# projects, you need to add all the files into the projects file 😉

So you need to update the Meplato.Store2.Tests.csproj file, because right now all your new test data files and the Availabilities tests aren't part of the project. And therefore aren't executed.

[m-timmermann]

Added the testdata and testfiles to the Meplato.Store2.Tests.csproj

[MCwolek]

Please check my comments below. After these changes, I was able to run all tests successfully.

[MCwolek]

If you change in all Availabilities test files the class definition to use : Tests.TestCase instead of : TestCase, then you can delete this file here.
I know, you only copy-paste it from the other test cases. But it's only an additional file that does nothing else. So no need for it, right?

[MCwolek]

Suggested change

	HTTP/1.1 200
	HTTP/1.1 404 Not Found

[m-timmermann]

This currently returns a 200 with the following json Data

{
    "kind": "store#availabilities/getResponse",
    "items": null,
    "Error": null
}

[MCwolek]

OK, are you sure you want to leave it this way? 🤔 Every other service (Catalogs, Jobs, Products) in the .Net client throws in the Get endpoint an execution when the requested item doesn't exist.
So the Availabilities service behaves differently, which doesn't feel good TBH, it's not consistent.

[MCwolek]

Suggested change

	"kind": "store#availabilities/getResponse",
	"items": null,
	"Error": null
	"error": {
	"message": "Availability not found"
	}

[MCwolek]

Test will fail, because an exception is thrown for an unknown product, so you need to change the assertion:

Suggested change

	var response = await service.Get().Spn("no-such-product").Do();
	Assert.NotNull(response);
	Assert.NotNull(response.Kind);
	Assert.AreEqual("store#availabilities/getResponse", response.Kind);
	Assert.Null(response.Items);
	var ex = Assert.ThrowsAsync<ServiceException>(() => service.Get().Spn("no-such-product").Do());
	Assert.NotNull(ex);

[MCwolek]

LGTM 👍🏽

Maybe it should be discussed what to do about the Get endpoint in the Availabilities service, because it does behave differently.