Add unit tests for formatting output
user
```ruby

# This seems wrong, but I don't actually know how to do this
require_relative '../../libraries/icinga2.rb'

describe "#icinga_format" do
  subject { icinga_format }

  it "handles hashes" do
    expect(icinga_format({:foo => :bar})).to eq('{ "foo" = "bar" }')
  end

  it "handles arrays" do
    expect(icinga_format([1,3,5])).to eq('[ 1, 3, 5 ]')
  end

  it "handles strings" do
    expect(icinga_format("foo")).to eq('"foo"')
  end

  it "handles floats" do
    expect(icinga_format(1.2)).to eq('1.2')
  end

  it "handles fixnums" do
    expect(icinga_format(10)).to eq('10')
  end

  it "handles nulls" do
    expect(icinga_format(nil)).to eq("null")
  end

  it "handles nesting" do
    expect(icinga_format({:foo => [:bar, {1=>2}, {1=>[:a,:b,:c]}]})).to eq('{ "foo" = [ "bar", { 1 = 2 }, { 1 = [ "a", "b", "c" ] } ] }')
  end

  it "handles arbitrary objects by stringifying them" do
    expect(icinga_format(StandardError.new)).to eq('"#<StandardError: StandardError>"')
  end

  it "Arbitrary stringifying works with nesting" do
    expect(icinga_format({"err"=>StandardError.new, "list"=>[{"err"=>IOError.new}]})).to eq('{ "err" = "#<StandardError: StandardError>", "list" = [ { "err" = "#<IOError: IOError>" } ] }')
  end

end
```
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