feat: Finish LinkedList methods

Author: BraisonCrece

.gitignote

@@ -1 +1 @@
-.byebug_history
+byebug_history

data-structures/LinkedList/linked_list.rb

@@ -3,68 +3,94 @@
 class LinkedList
   attr_accessor :head, :tail
 
-  def add(value)
-    node = Node.new(value)
-    node.value = value
-    if !head
-      @head = node
-      @tail = node
+  def append(value)
+    raise ArgumentError.new("Error: Invalid value") if value.nil?
+    new_node = Node.new(value)
+    new_node.previous_node = @tail
+    @tail.next_node = new_node if @tail
+    @tail = new_node
+    @head ||= new_node
+    "Success: Value '#{value}' was appended"
+  rescue => exception
+    warn exception.message
+  end
+
+  def prepend(value)
+    raise ArgumentError.new("Error: Invalid value") if value.nil?
+    new_node = Node.new(value)
+    new_node.next_node = @head
+    @head.previous_node = new_node if @head
+    @head = new_node
+    @tail ||= new_node
+    "Success: Value '#{value}' was prepended"
+  rescue => exception
+    warn exception.message
+  end
+
+  def insert_at(index, value)
+    raise ArgumentError.new("Error: Invalid value") if value.nil?
+    raise IndexError.new("Error: Index out of bounds") if index < 0 || index > size
+    raise StandardError.new("Error: The list is empty") if size == 0
+
+    case index
+    when 0
+      prepend(value)
+    when size
+      append(value)
     else
-      node.previous_node = @tail
-      @tail.next_node = node
-      @tail = node
+      new_node = Node.new(value)
+      prev_node = select_node(index - 1)
+      next_node = select_node(index)
+
+      prev_node.next_node = new_node
+      new_node.previous_node = prev_node
+      new_node.next_node = next_node
+      next_node.previous_node = new_node
     end
-    "success"
+    "Success: Value '#{value}' was inserted at index #{index}"
+  rescue => exception
+    warn exception.message
   end
 
   def get(index)
-    begin
-      return @head.value if index === 0
-      node = select_node(index)
-      raise "INDEX #{index} OUT OF BOUNDS" if !node
-      node.value
-    rescue => exception
-      p "#{exception.message}"
-    end
+    raise StandardError.new("Error: The list is empty") if size === 0
+    return @head.value if index === 0
+    node = select_node(index)
+    raise IndexError.new("Index #{index} out of bounds") if !node
+    node.value
+  rescue => exception
+    warn exception.message
   end
 
   def replace(index, new_value)
-    begin
-      node_to_replace = select_node(index)
-      raise "INDEX #{index} OUT OF BOUNDS" if !node_to_replace
-      # Replace the value directly
-      node_to_replace.value = new_value
-      new_value # This should be the replaced node's value
-    rescue => exception
-      p "#{exception.message}"
-    end
+    raise StandardError.new("Error: The list is empty") if size === 0
+    node_to_replace = select_node(index)
+    raise IndexError.new("Index #{index} out of bounds") unless node_to_replace
+    node_to_replace.value = new_value
+  rescue => exception
+    warn exception.message
   end
 
   def remove(index)
-    begin
-      # if the node is the head
-      if index === 0
-        @head.next_node.previous_node = nil
-        @head = @head.next_node
-        return
-      end
-
-      node = select_node(index)
-      raise "INDEX #{index} OUT OF BOUNDS" if !node
-      # if the node is the tail
-      if !node.next_node
-        node.previous_node.next_node = nil
-        @tail = node.previous_node
-        return
-      end
+    raise StandardError.new("Error: The list is empty") if size === 0
+    if index === 0
+      @head.next_node.previous_node = nil
+      @head = @head.next_node
+      return
+    end
 
-      # if the node is in the middle
-      node.previous_node.next_node = node.next_node
-      node.next_node.previous_node = node.next_node
+    node = select_node(index)
+    raise IndexError.new("Index #{index} out of bounds") if !node
+    if !node.next_node
+      node.previous_node.next_node = nil
+      @tail = node.previous_node
       return
-    rescue => exception
-      p "#{exception.message}"
     end
+
+    node.previous_node.next_node = node.next_node
+    node.next_node.previous_node = node.next_node
+  rescue => exception
+    warn exception.message
   end
 
   def inspect
@@ -78,7 +104,7 @@ def inspect
   end
 
   def size
-    return 0 if @head === nil
+    return 0 if @head.nil?
     size = 1
     node = @head
     while node.next_node

spec/linked_list_spec.rb

@@ -1,81 +1,153 @@
+# frozen_string_literal: true
+
 require_relative "../data-structures/LinkedList/linked_list"
-require "byebug"
+
 RSpec.describe LinkedList do
-  let(:linked_list) { LinkedList.new }
+  context "with an empty list" do
+    describe "#append" do
+      it "adds a value to the enf of the list" do
+        expect(subject.append("First Value")).to eq "Success: Value 'First Value' was appended"
+        expect(subject.head.value).to eq "First Value"
+        expect(subject.tail.value).to eq "First Value"
+        expect(subject.size).to eq 1
+      end
+    end
 
-  describe "#add" do
-    it "adds a value to the linked list" do
-      expect(linked_list.add("First Value")).to eq "success"
-      expect(linked_list.head.value).to eq "First Value"
-      expect(linked_list.tail.value).to eq "First Value"
+    describe "#prepend" do
+      it "adds a value at the start of the list" do
+        expect(subject.prepend("New first value")).to eq "Success: Value 'New first value' was prepended"
+        expect(subject.head.value).to eq "New first value"
+        expect(subject.tail.value).to eq "New first value"
+      end
     end
-  end
 
-  describe "#get" do
-    it "gets the value at a given index" do
-      linked_list.add("First Value")
-      linked_list.add("Second Value")
-      expect(linked_list.get(1)).to eq "Second Value"
+    describe "#isert_at" do
+      it "show an error" do
+        expect { subject.insert_at(0, "First value") }.to output("Error: The list is empty\n").to_stderr
+      end
     end
 
-    it "returns error message if index out of bounds" do
-      expect(linked_list.get(10)).to eq "INDEX 10 OUT OF BOUNDS"
+    describe "#get" do
+      it "returns error message if list is empty" do
+        expect { subject.get(0) }.to output("Error: The list is empty\n").to_stderr
+      end
     end
-  end
 
-  describe "#replace" do
-    before do
-      linked_list.add("First Value")
-      linked_list.add("Second Value")
+    describe "#replace" do
+      it "returns error message if list is empty" do
+        expect { subject.replace(0, "New Value") }.to output("Error: The list is empty\n").to_stderr
+      end
+    end
+
+    describe "#remove" do
+      it "returns error message if the list is empty" do
+        expect { subject.remove(0) }.to output("Error: The list is empty\n").to_stderr
+      end
     end
 
-    it "replaces the value at a given index" do
-      linked_list.replace(1, "New First Value")
-      expect(linked_list.get(1)).to eq "New First Value"
+    describe "#inspect" do
+      it "prints the linked list" do
+        expect(subject.inspect).to eq []
+      end
     end
 
-    it "returns error message if index out of bounds" do
-      expect(linked_list.replace(10, "New Value")).to eq "INDEX 10 OUT OF BOUNDS"
+    describe "#size" do
+      it "returns 0 if the linked list is empty" do
+        expect(subject.size).to eq 0
+      end
     end
   end
 
-  describe "#remove" do
+  context "whit nodes already in the list" do
     before do
-      linked_list.add("First Value")
-      linked_list.add("Second Value")
+      subject.append("First Value")
+      subject.append("Second Value")
     end
 
-    it "removes the value at a given index" do
-      linked_list.remove(0)
-      expect(linked_list.get(0)).to eq "Second Value"
+    describe "#append" do
+      it "adds a value to the enf of the list" do
+        expect(subject.append("Third Value")).to eq "Success: Value 'Third Value' was appended"
+        expect(subject.head.value).to eq "First Value"
+        expect(subject.tail.value).to eq "Third Value"
+        expect(subject.size).to eq 3
+      end
     end
 
-    it "returns error message if index out of bounds" do
-      expect(linked_list.remove(10)).to eq "INDEX 10 OUT OF BOUNDS"
+    describe "#prepend" do
+      it "adds a value at the start of the list" do
+        expect(subject.prepend("New first value")).to eq "Success: Value 'New first value' was prepended"
+        expect(subject.head.value).to eq "New first value"
+        expect(subject.tail.value).to eq "Second Value"
+      end
     end
-  end
 
-  describe "#inspect" do
-    before do
-      linked_list.add("First Value")
-      linked_list.add("Second Value")
+    describe "#isert_at" do
+      it "inserts the node on index 0" do
+        expect(subject.size).to eq 2
+        expect(subject.insert_at(0, "New node")).to eq "Success: Value 'New node' was inserted at index 0"
+        expect(subject.head.value).to eq "New node"
+        expect(subject.size).to eq 3
+      end
+
+      it "inserts the node on the last index" do
+        expect(subject.size).to eq 2
+        expect(subject.insert_at(2, "New node")).to eq "Success: Value 'New node' was inserted at index 2"
+        expect(subject.tail.value).to eq "New node"
+        expect(subject.size).to eq 3
+      end
+
+      it "inserts the new node in the middle" do
+        expect(subject.size).to eq 2
+        expect(subject.insert_at(1, "New node")).to eq "Success: Value 'New node' was inserted at index 1"
+        expect(subject.head.value).to eq "First Value"
+        expect(subject.tail.value).to eq "Second Value"
+        expect(subject.size).to eq 3
+      end
     end
 
-    it "prints the linked list" do
-      expect(linked_list.inspect).to eq ["First Value", "Second Value"]
+    describe "#get" do
+      it "gets the value at a given index" do
+        expect(subject.get(1)).to eq "Second Value"
+      end
+
+      it "returns error message if index out of bounds" do
+        expect { subject.get(10) }.to output("Index 10 out of bounds\n").to_stderr
+      end
+    end
+
+    describe "#replace" do
+      it "replaces the value at a given index" do
+        subject.replace(1, "New First Value")
+        expect(subject.get(1)).to eq "New First Value"
+      end
+
+      it "returns error message if index out of bounds" do
+        expect { subject.replace(10, "New Value") }.to output("Index 10 out of bounds\n").to_stderr
+      end
+    end
+
+    describe "#remove" do
+      it "removes the value at a given index" do
+        subject.remove(0)
+        expect(subject.get(0)).to eq "Second Value"
+      end
+
+      it "returns error message if index out of bounds" do
+        expect { subject.remove(10) }.to output("Index 10 out of bounds\n").to_stderr
+      end
     end
-  end
 
-  describe "#size" do
-    it "returns the size of the linked list" do
-      linked_list.add("First Value")
-      linked_list.add("Second Value")
-      linked_list.add("Third Value")
-      expect(linked_list.size).to eq 3
+    describe "#inspect" do
+      it "prints the linked list" do
+        expect(subject.inspect).to eq ["First Value", "Second Value"]
+      end
     end
 
-    it "returns 0 if the linked list is empty" do
-      expect(linked_list.size).to eq 0
+    describe "#size" do
+      it "returns the size of the linked list" do
+        subject.append("Third Value")
+        expect(subject.size).to eq 3
+      end
     end
   end
 end