Tough Time Spec'ing Exit

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Dang.

I really wanted to move on, but I think I need to add a code generator for new map, reduces and libraries. I think it would be helpful to be able to generate a map-reduce for recipes by date with this command:

couch-docs generate map-reduce recipes by_date

After some searching, I came across the rubygen gem which seems like it might do the trick. I install with:

cstrom@whitefall:~/repos/couch_docs$ gem install rubigen
WARNING:  Installing to ~/.gem since /var/lib/gems/1.8 and
          /var/lib/gems/1.8/bin aren't both writable.
Successfully installed rubigen-1.5.4
1 gem installed

Hrm. It looks like rubigen requires activesupport:

$:.unshift(File.dirname(__FILE__)) unless
  $:.include?(File.dirname(__FILE__)) || $:.include?(File.expand_path(File.dirname(__FILE__)))

begin
  # if you are using rubygems, fix to 2.3.5
  gem 'activesupport', '2.3.5'
rescue
end

require 'active_support' 
                          
module RubiGen
  VERSION = '1.5.4'
end
...

ActiveSupport seems a bit much. RubiGen is something intended more for rolling your own framework.

So, even though it will mean a less awesome generator, I will roll my own. I start with an RSpec example over the command line:

  context "generate" do
    it "should fail with unknown generators" do
      @it = CommandLine.new(['generate', 'foo'])
      Kernel.should_receive(:exit)
      @it.run
    end

That fails with:

1)
SystemExit in 'CouchDocs::CommandLine generate should fail with unknown generators'
exit
./spec/couch_docs_spec.rb:439:in `new'
./spec/couch_docs_spec.rb:439:

Ugh. SystemExit? What's that all about? Ah, there is some output in my spec run:

.......invalid command: "generate".  Must be one of push, dump.

Usage: couch-docs push|dump [OPTIONS] couchdb_url [target_dir]

Try --help for more options.
F

Ah, I really am in the normal change-the-message or make-it-pass cycle. In this case, I need to add to the list of know commands:

And then handle the new generate command:

...
        if @command == "generate"
          puts "Invalid generator #{args.first}"
          exit
        else
          # handle push/dump
...

Running the examples, I get:

1)
SystemExit in 'CouchDocs::CommandLine generate should fail with unknown generators'
exit
./spec/couch_docs_spec.rb:439:in `new'
./spec/couch_docs_spec.rb:439:

Hunh? Shouldn't that should_receive exit prevent that error?

Sadly, it takes me a loooong time to realize that exit is occurring in the new, not the run so I have to rearrange when I set my expectation for an exit:

    it "should fail with unknown generators" do
      Kernel.should_receive(:exit)
      @it = CommandLine.new(['generate', 'foo'])
    end

Running the example, I now find... the exact same thing:

1)
SystemExit in 'CouchDocs::CommandLine generate should fail with unknown generators'
exit
./spec/couch_docs_spec.rb:440:in `new'
./spec/couch_docs_spec.rb:440:

Gah!

At this point, I have to resort to catching exceptions on lambdas:

    it "should fail with unknown generators" do
      lambda {
        CommandLine.new(['generate', 'foo'])
      }.should raise_error SystemExit
    end

That finally gets the example passing.

Rather than stumble any further, I will call it a night at this point and hope for better fortune tomorrow.

Day #41