compressor_spec.rb in rambling-trie-1.0.3

- old
+ new
@@ -2,30 +2,105 @@
 
 describe Rambling::Trie::Compressor do
   let(:compressor) { Rambling::Trie::Compressor.new }
 
   describe '#compress' do
-    let(:words) { %w(a few words hello hell) }
-    let(:root) do
-      Rambling::Trie::RawNode.new
+    let(:node) { Rambling::Trie::Nodes::Raw.new }
+
+    it 'compresses the node' do
+      add_words node, %w(a few words hello hell)
+      compressed = compressor.compress node
+
+      expect(compressed.children_tree.keys).to eq %i(a few words hell)
     end
 
-    before do
-      words.each { |w| root.add w.clone }
+    context 'with at least one word' do
+      before do
+        add_words node, %w(all the words)
+      end
+
+      it 'keeps the node letter nil' do
+        compressed = compressor.compress node
+
+        expect(compressed.letter).to be_nil
+      end
     end
 
-    it 'generates a new root with the words from the passed root' do
-      new_root = compressor.compress root
+    context 'with a single word' do
+      before do
+        add_word node, 'all'
+      end
 
-      expect(words).not_to be_empty
-      words.each do |word|
-        expect(new_root).to include word
+      it 'compresses into a single node without children' do
+        compressed = compressor.compress node
+
+        expect(compressed[:all].letter).to eq :all
+        expect(compressed[:all].children.size).to eq 0
+        expect(compressed[:all]).to be_terminal
+        expect(compressed[:all]).to be_compressed
       end
     end
 
-    it 'compresses the new root' do
-      new_root = compressor.compress root
+    context 'with two words' do
+      before do
+        add_words node, %w(all ask)
+      end
 
-      expect(new_root.children_tree.keys).to eq %i(a few words hell)
+      it 'compresses into corresponding three nodes' do
+        compressed = compressor.compress node
+
+        expect(compressed[:a].letter).to eq :a
+        expect(compressed[:a].children.size).to eq 2
+
+        expect(compressed[:a][:ll].letter).to eq :ll
+        expect(compressed[:a][:sk].letter).to eq :sk
+
+        expect(compressed[:a][:ll].children.size).to eq 0
+        expect(compressed[:a][:sk].children.size).to eq 0
+
+        expect(compressed[:a][:ll]).to be_terminal
+        expect(compressed[:a][:sk]).to be_terminal
+
+        expect(compressed[:a][:ll]).to be_compressed
+        expect(compressed[:a][:sk]).to be_compressed
+      end
+    end
+
+    it 'reassigns the parent nodes correctly' do
+      add_words node, %w(repay rest repaint)
+      compressed = compressor.compress node
+
+      expect(compressed[:re].letter).to eq :re
+      expect(compressed[:re].parent).to eq compressed
+      expect(compressed[:re].children.size).to eq 2
+
+      expect(compressed[:re][:pa].letter).to eq :pa
+      expect(compressed[:re][:pa].parent).to eq compressed[:re]
+      expect(compressed[:re][:pa].children.size).to eq 2
+
+      expect(compressed[:re][:st].letter).to eq :st
+      expect(compressed[:re][:st].parent).to eq compressed[:re]
+      expect(compressed[:re][:st].children.size).to eq 0
+
+      expect(compressed[:re][:pa][:y].letter).to eq :y
+      expect(compressed[:re][:pa][:y].parent).to eq compressed[:re][:pa]
+      expect(compressed[:re][:pa][:y].children.size).to eq 0
+
+      expect(compressed[:re][:pa][:int].letter).to eq :int
+      expect(compressed[:re][:pa][:int].parent).to eq compressed[:re][:pa]
+      expect(compressed[:re][:pa][:int].children.size).to eq 0
+    end
+
+    it 'does not compress terminal nodes' do
+      add_words node, %w(you your yours)
+      compressed = compressor.compress node
+
+      expect(compressed[:you].letter).to eq :you
+
+      expect(compressed[:you][:r].letter).to eq :r
+      expect(compressed[:you][:r]).to be_compressed
+
+      expect(compressed[:you][:r][:s].letter).to eq :s
+      expect(compressed[:you][:r][:s]).to be_compressed
     end
   end
 end