Add tests for DataBinding::Hiera#find and #convert_merge

The convert_merge method has significant branching logic that was
never covered by unit tests - the deleted Puppet::Indirector::Hiera
spec only exercised the shared Hiera indirection behaviours. Add
explicit tests for all convert_merge branches (nil/first, unique,
hash, deep, Hash with strategy, MergeStrategy delegation, and the
error path) and for the :no_such_key throw in find when Hiera returns
its not-found sentinel.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Steven Pritchard <steven.pritchard@gmail.com>

Author: silug

spec/unit/indirector/data_binding/hiera_spec.rb

@@ -16,4 +16,73 @@
   end
 
   it_should_behave_like "Hiera indirection", Puppet::DataBinding::Hiera, my_fixture_dir
+
+  describe "#find", :if => Puppet.features.hiera? do
+    let(:data_binder) { described_class.new }
+    let(:hiera)       { double('hiera') }
+
+    def request(key, options = {})
+      Puppet::Indirector::Request.new(:hiera, :find, key, nil, options)
+    end
+
+    before do
+      allow(described_class).to receive(:hiera).and_return(hiera)
+    end
+
+    it "throws :no_such_key when hiera returns the not_found sentinel" do
+      # Returning the default argument signals "not found" to the find method
+      allow(hiera).to receive(:lookup) { |_key, default, *_| default }
+      expect { data_binder.find(request('missing')) }.to throw_symbol(:no_such_key)
+    end
+  end
+
+  describe "#convert_merge", :if => Puppet.features.hiera? do
+    let(:data_binder) { described_class.new }
+
+    def convert(merge)
+      data_binder.send(:convert_merge, merge)
+    end
+
+    it "returns nil for nil" do
+      expect(convert(nil)).to be_nil
+    end
+
+    it "returns nil for 'first'" do
+      expect(convert('first')).to be_nil
+    end
+
+    it "returns :array for 'unique'" do
+      expect(convert('unique')).to eq(:array)
+    end
+
+    it "returns native hash behavior for 'hash'" do
+      expect(convert('hash')).to eq({ :behavior => :native })
+    end
+
+    it "returns deeper hash behavior for 'deep'" do
+      expect(convert('deep')).to eq({ :behavior => :deeper })
+    end
+
+    it "delegates to the strategy's configuration when given a MergeStrategy" do
+      strategy = instance_double(Puppet::Pops::MergeStrategy, :configuration => 'unique')
+      expect(convert(strategy)).to eq(:array)
+    end
+
+    it "returns deeper hash behavior for a Hash with strategy 'deep'" do
+      expect(convert({ 'strategy' => 'deep' })).to eq({ :behavior => :deeper })
+    end
+
+    it "forwards extra keys alongside deeper behavior for a Hash with strategy 'deep'" do
+      result = convert({ 'strategy' => 'deep', 'knockout_prefix' => '--' })
+      expect(result).to eq({ :behavior => :deeper, :knockout_prefix => '--' })
+    end
+
+    it "delegates to the string strategy for a Hash with a non-deep strategy" do
+      expect(convert({ 'strategy' => 'unique' })).to eq(:array)
+    end
+
+    it "raises LookupError for an unrecognized merge value" do
+      expect { convert('bogus') }.to raise_error(Puppet::DataBinding::LookupError, /Unrecognized value.*bogus/)
+    end
+  end
 end