Writing Rspec Tests w/Mocha

[John Julien]

Hi,

I'm adding the feature :libuser to Puppet::Type::Group.  In the groupadd provider, having the feature libuser and setting forcelocal => true will cause the invoked command to be lgroupadd instead of groupadd.  I want to write a test case for both when the libuser feature is present and when its not.   

I'm seeing a lot of test cases written like:

   describe "on system that feature system_groups", :if => described_class.system_groups? do

This appears to restrict the test case from being run only on systems that actually support the system_groups feature.  I would like to write a test case that, within the groupadd provider, emulates both having and not having the libuser feature and making sure that the command lgroupadd and groupadd are used respectively.

I thought I could accomplish this by executing

   provider.stubs(:feature?).with(:libuser).returns(true)

But I end up getting unexpected invocation errors because provider.features? gets executed by Puppet::Type::Group with other parameters than :libuser.

Here's the full details:

https://github.com/jjulien/puppet/commit/c89c65fd703f20d539966f42fe4cb826bd1ca6b7

Any advice on the test case would be greatly appreciated.

John

[Dominic Cleal]

On 18/01/13 07:30, John Julien wrote:
> Hi,
> I'm adding the feature :libuser to Puppet::Type::Group. In the groupadd
> provider, having the feature libuser and setting forcelocal => true will
> cause the invoked command to be lgroupadd instead of groupadd. I want
> to write a test case for both when the libuser feature is present and
> when its not.
>
> I'm seeing a lot of test cases written like:
> describe "on system that feature system_groups", :if =>
> described_class.system_groups? do
>
> This appears to restrict the test case from being run only on systems
> that actually support the system_groups feature. I would like to write
> a test case that, within the groupadd provider, emulates both having and
> not having the libuser feature and making sure that the command
> lgroupadd and groupadd are used respectively.
>
> I thought I could accomplish this by executing
> provider.stubs(:feature?).with(:libuser).returns(true)
>
> But I end up getting unexpected invocation errors because
> provider.features? gets executed by Puppet::Type::Group with other
> parameters than :libuser.

The method you want to stub is actually on Puppet.features:

has_feature :libuser if Puppet.features.libuser?

So you'd be using:

Puppet.features.expects(:libuser?).returns(true)

The trouble in this case, and the reason I think the other tests only
run on systems with those features, is that *provider* features aren't
re-evaluated at all.

This is logged as issue #2384, but it's mostly a problem for libraries
which can be installed during a run and require re-evaluation of features.

When the provider is initially evaluated, the if feature statement is
going to get evaluated, but not again. This means if you come to stub
the *system* libuser feature in the test harness, it won't change the
evaluation that's already happened for the provider's feature.

I think if you're going to implement this as a provider feature, you'll
have to test it in a similar way to system_groups.

--
Dominic Cleal
Red Hat Engineering

[John Julien]

I am new to Mocha and writing unit tests in general so please do correct if this is wrong.

I would think I should be able to test for the proper invocation of the lgroupadd command vs. the groupadd command, even on a system that does not contain the libuser package.

Doing some more looking around and reading, I came up with code which will execute a test for the "forcelocal" parameter even on systems that do not contain libuser. Since the command is not really being executed on the system, just evaluated, this should cause no problems. I removed the libuser capabilities from my machine and this test was still executed and passed correctly.

it "should use luseradd instead of useradd when forcelocal=true" do
described_class.has_feature :libuser
resource[:forcelocal] = :true
provider.expects(:execute).with(includes('/usr/sbin/luseradd'))
provider.create
end

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[Andy Parker]

On Fri, Jan 18, 2013 at 10:23 AM, John Julien <jo...@julienfamily.com> wrote:

I am new to Mocha and writing unit tests in general so please do correct if this is wrong.

I would think I should be able to test for the proper invocation of the lgroupadd command vs. the groupadd command, even on a system that does not contain the libuser package.

Doing some more looking around and reading, I came up with code which will execute a test for the "forcelocal" parameter even on systems that do not contain libuser.  Since the command is not really being executed on the system, just evaluated, this should cause no problems.  I removed the libuser capabilities from my machine and this test was still executed and passed correctly.

   it "should use luseradd instead of useradd when forcelocal=true" do
     described_class.has_feature :libuser
     resource[:forcelocal] = :true
     provider.expects(:execute).with(includes('/usr/sbin/luseradd'))
     provider.create
   end

That all looks pretty reasonable to me.