ec2test: handle CreateTags action

[axw]

This commit adds support for the CreateTags
action to the test server, and an accompanying
test. Live tested.

[wallyworld]

tag limit exceeded should be a separate test, strictly speaking
similar to create tags invalid test below

[axw]

done

[wallyworld]

is this right? it will append to tags slice but the slot it ends up in won't necessarily match i

what if we have:

Tag.1.Key
Tag.1.Value
Tag.3.Key
Tag.3.Value

then the tag 3 value will end up in the slot for tag 2.

Is the above possible? Or is it enforced that there must be a tag 1 and tag 2 and tag 3 etc, not missing values like tag 1 and tag 2 and tag4. Either way, I think another test is needed

[axw]

Tag.1.Key
Tag.1.Value

At this point: tags is empty, i is 1. It'll add a single empty ec2.Tag to tags, and then below will set the i-1'th element (i.e. index 0 in this case) to the key/value.

tags == []ec2.Tag{{"Tag.1.Key", "Tag.1.Value"}}

Tag.3.Key
Tag.3.Value

Now tags has len==1, and i is 3. The code will add two empty ec2.Tags to tags, and below will set the element at index 2 to the key/value. So at this point we'd have:

tags == []ec2.Tag{{"Tag.1.Key", "Tag.1.Value"}, {}, {"Tag.2.Key", "Tag.2.Value"}}

Is the above possible? Or is it enforced that there must be a tag 1 and tag 2 and tag 3 etc, not missing values like tag 1 and tag 2 and tag4. Either way, I think another test is needed

The values are going in the right places. I'd say it's an error to have non-contiguous sequence numbers. We don't have to test every possible scenario in the test server, though; only the ones that we actually run. We will never generate such parameters, so it's not worth trying to bend the code to test it.

[wallyworld]

LGTM with question about tags either answered or fixed