diff --git a/bin/test/bundler-app b/bin/test/bundler-app
index f5f2bc61..4f4ae60f 100755
--- a/bin/test/bundler-app
+++ b/bin/test/bundler-app
@@ -1,7 +1,14 @@
 #!/usr/bin/env bash
 
+FOLDER="features/bundler-app"
+
 bundle install
 bundle exec rake build
-cp -R features/support features/bundler-app/retest
-ls -t pkg | head -n1 | xargs -I {} mv pkg/{} features/bundler-app/retest.gem
-docker compose -f features/bundler-app/docker-compose.yml up --build --exit-code-from retest
\ No newline at end of file
+# cp -R features/support features/bundler-app/retest
+ls -t pkg | head -n1 | xargs -I {} mv pkg/{} "$FOLDER/retest.gem"
+
+if [[ "$1" == "--no-build" ]]; then
+	docker compose -f "$FOLDER/docker-compose.yml" up --exit-code-from retest
+else
+	docker compose -f "$FOLDER/docker-compose.yml" up --build --exit-code-from retest
+fi
diff --git a/features/bundler-app/lib/bundler_app.rb b/features/bundler-app/lib/bundler_app.rb
index 68855085..503d8b28 100644
--- a/features/bundler-app/lib/bundler_app.rb
+++ b/features/bundler-app/lib/bundler_app.rb
@@ -2,6 +2,7 @@
 
 require_relative "bundler_app/version"
 require_relative "bundler_app/bottles"
+require_relative "bundler_app/fibonacci"
 
 module BundlerApp
   class Error < StandardError; end
diff --git a/features/bundler-app/lib/bundler_app/fibonacci.rb b/features/bundler-app/lib/bundler_app/fibonacci.rb
new file mode 100644
index 00000000..7ee4feea
--- /dev/null
+++ b/features/bundler-app/lib/bundler_app/fibonacci.rb
@@ -0,0 +1,11 @@
+# fibonacci.rb
+class Fibonacci
+  def self.calculate(n)
+    raise ArgumentError, "Input must be a non-negative integer." unless n.is_a?(Integer) && n >= 0
+    return n if n <= 1
+
+    a, b = 0, 1
+    (n - 1).times { a, b = b, a + b }
+    b
+  end
+end
\ No newline at end of file
diff --git a/features/bundler-app/retest/retest_test.rb b/features/bundler-app/retest/retest_test.rb
index 3c22c4e4..0f4b5c32 100644
--- a/features/bundler-app/retest/retest_test.rb
+++ b/features/bundler-app/retest/retest_test.rb
@@ -2,8 +2,6 @@
 require_relative 'support/test_helper'
 require 'minitest/autorun'
 require_relative 'retest_test/file_changes_test'
+require_relative 'retest_test/interactive_commands_test'
 
 $stdout.sync = true
-
-include FileHelper
-
diff --git a/features/bundler-app/retest/retest_test/file_changes_test.rb b/features/bundler-app/retest/retest_test/file_changes_test.rb
index ea08577a..3938e6b7 100644
--- a/features/bundler-app/retest/retest_test/file_changes_test.rb
+++ b/features/bundler-app/retest/retest_test/file_changes_test.rb
@@ -1,4 +1,6 @@
 class FileChangesTest < Minitest::Test
+  include RetestHelper
+
   def setup
     @command = 'retest'
   end
@@ -10,7 +12,7 @@ def teardown
   def test_start_retest
     launch_retest @command
 
-    assert_match <<~EXPECTED, @output.read
+    assert_output_matches <<~EXPECTED
       Launching Retest...
       Ready to refactor! You can make file changes now
     EXPECTED
@@ -21,8 +23,9 @@ def test_modifying_existing_file
 
     modify_file('lib/bundler_app/bottles.rb')
 
-    assert_match "Test file: test/bundler_app/test_bottles.rb", @output.read
-    assert_match "12 runs, 12 assertions, 0 failures, 0 errors, 0 skips", @output.read
+    assert_output_matches(
+      'Test file: test/bundler_app/test_bottles.rb',
+      '12 runs, 12 assertions, 0 failures, 0 errors, 0 skips')
   end
 
   def test_modifying_existing_test_file
@@ -30,8 +33,9 @@ def test_modifying_existing_test_file
 
     modify_file('test/bundler_app/test_bottles.rb')
 
-    assert_match "Test file: test/bundler_app/test_bottles.rb", @output.read
-    assert_match "12 runs, 12 assertions, 0 failures, 0 errors, 0 skips", @output.read
+    assert_output_matches(
+      'Test file: test/bundler_app/test_bottles.rb',
+      '12 runs, 12 assertions, 0 failures, 0 errors, 0 skips')
   end
 
   def test_creating_a_new_test_file
@@ -39,7 +43,7 @@ def test_creating_a_new_test_file
 
     create_file 'test/bundler_app/test_foo.rb'
 
-    assert_match "Test file: test/bundler_app/test_foo.rb", @output.read
+    assert_output_matches 'Test file: test/bundler_app/test_foo.rb'
 
   ensure
     delete_file 'test/bundler_app/test_foo.rb'
@@ -49,18 +53,16 @@ def test_creating_a_new_file
     launch_retest @command
 
     create_file 'lib/bundler_app/foo.rb'
-    assert_match <<~EXPECTED, @output.read
-      FileNotFound - Retest could not find a matching test file to run.
-    EXPECTED
+    assert_output_matches 'FileNotFound - Retest could not find a matching test file to run.'
 
     create_file 'test/bundler_app/test_foo.rb'
-    assert_match "Test file: test/bundler_app/test_foo.rb", @output.read
+    assert_output_matches 'Test file: test/bundler_app/test_foo.rb'
 
     modify_file('lib/bundler_app/bottles.rb')
-    assert_match "Test file: test/bundler_app/test_bottles.rb", @output.read
+    assert_output_matches 'Test file: test/bundler_app/test_bottles.rb'
 
     modify_file('lib/bundler_app/foo.rb')
-    assert_match "Test file: test/bundler_app/test_foo.rb", @output.read
+    assert_output_matches 'Test file: test/bundler_app/test_foo.rb'
 
   ensure
     delete_file 'lib/bundler_app/foo.rb'
@@ -68,13 +70,13 @@ def test_creating_a_new_file
   end
 
   def test_untracked_file
-    create_file 'lib/bundler_app/foo.rb', should_sleep: false
-    create_file 'test/bundler_app/test_foo.rb', should_sleep: false
+    create_file 'lib/bundler_app/foo.rb', sleep_for: 0
+    create_file 'test/bundler_app/test_foo.rb', sleep_for: 0
 
     launch_retest @command
 
     modify_file 'lib/bundler_app/foo.rb'
-    assert_match "Test file: test/bundler_app/test_foo.rb", @output.read
+    assert_output_matches 'Test file: test/bundler_app/test_foo.rb'
 
   ensure
     delete_file 'lib/bundler_app/foo.rb'
diff --git a/features/bundler-app/retest/retest_test/interactive_commands_test.rb b/features/bundler-app/retest/retest_test/interactive_commands_test.rb
new file mode 100644
index 00000000..46d7d93e
--- /dev/null
+++ b/features/bundler-app/retest/retest_test/interactive_commands_test.rb
@@ -0,0 +1,141 @@
+class InteractiveCommandTest < Minitest::Test
+  include RetestHelper
+
+  def setup
+    @command = 'retest'
+  end
+
+  def teardown
+    end_retest
+  end
+
+  def test_start_help
+    launch_retest @command
+
+    assert_output_matches <<~EXPECTED.chomp
+      Setup identified: [RAKE]. Using command: 'bundle exec rake test TEST=<test>'
+      Watcher: [LISTEN]
+      Launching Retest...
+      Ready to refactor! You can make file changes now
+
+      Type interactive command and press enter. Enter 'h' for help.
+      >\s
+    EXPECTED
+
+    write_input("h\n")
+
+    assert_output_matches <<~EXPECTED.chomp
+      * 'h', 'help'              # Prints help.
+      * 'p', 'pause'             # Pauses Retest. Tests aren't run on file change events until unpaused.
+      * 'u', 'unpause'           # Unpauses Retest.
+      * <ENTER>                  # Runs last changed triggered command.
+      * 'ra, 'run all'           # Runs all tests.
+      * 'f', 'force'             # Forces a selection of test to run on every file change.
+      * 'r', 'reset'             # Disables forced selection.
+      * 'd', 'diff' [GIT BRANCH] # Runs matching specs that changed from a target branch.
+      * 'e', 'exit'              # Exits Retest.
+
+      Type interactive command and press enter. Enter 'h' for help.
+      >\s
+    EXPECTED
+  end
+
+  def test_pause_unpause
+    launch_retest @command
+
+    modify_file('lib/bundler_app/bottles.rb')
+
+    assert_output_matches(
+      "Test file: test/bundler_app/test_bottles.rb",
+      "12 runs, 12 assertions, 0 failures, 0 errors, 0 skips"
+    )
+
+    write_input("p\n")
+
+    assert_output_matches "Program is paused"
+
+    modify_file('lib/bundler_app/bottles.rb')
+
+    assert_output_matches <<~EXPECTED
+      File changed: lib/bundler_app/bottles.rb
+      Main program paused. Please resume program first.
+    EXPECTED
+
+    write_input("\n") # Manually run previous test
+
+    assert_output_matches(
+      "Running last command: 'bundle exec rake test TEST=test/bundler_app/test_bottles.rb'",
+      "12 runs, 12 assertions, 0 failures, 0 errors, 0 skips"
+    )
+
+    write_input("u\n")
+
+    modify_file('lib/bundler_app/bottles.rb')
+
+    assert_output_matches(
+      "Test file: test/bundler_app/test_bottles.rb",
+      "12 runs, 12 assertions, 0 failures, 0 errors, 0 skips"
+    )
+  end
+
+  def test_force_reset
+    launch_retest @command
+
+    write_input("f\n")
+
+    assert_output_matches "What test files do you want to run when saving a file? (min. 1)"
+
+    write_input("fib\s\n")
+
+    assert_output_matches <<~EXPECTED
+      Forced selection enabled.
+      Reset to default settings by typing 'r' in the interactive console.
+
+      Tests selected:
+        - test/bundler_app/test_fibonacci.rb
+    EXPECTED
+
+    assert_output_matches "8 runs, 9 assertions, 0 failures, 0 errors, 0 skips"
+
+    modify_file('lib/bundler_app/bottles.rb')
+
+    assert_output_matches <<~EXPECTED
+      Forced selection enabled.
+      Reset to default settings by typing 'r' in the interactive console.
+
+      Tests selected:
+        - test/bundler_app/test_fibonacci.rb
+    EXPECTED
+
+    write_input("\n") # Manually run previous test
+
+    assert_output_matches(
+      "Running last command: 'bundle exec rake test TEST=test/bundler_app/test_fibonacci.rb'",
+      "8 runs, 9 assertions, 0 failures, 0 errors, 0 skips"
+    )
+
+    write_input("r\n")
+
+    modify_file('lib/bundler_app/bottles.rb')
+
+    assert_output_matches(
+      "Test file: test/bundler_app/test_bottles.rb",
+      "12 runs, 12 assertions, 0 failures, 0 errors, 0 skips")
+  end
+
+  def test_run_all
+    launch_retest @command
+
+    write_input("ra\n")
+
+    assert_output_matches(
+      "Running all tests",
+      "21 runs, 22 assertions, 0 failures, 0 errors, 0 skips")
+
+    write_input("\n") # Manually run previous test
+
+    assert_output_matches(
+      "Running last command: 'bundle exec rake test",
+      "21 runs, 22 assertions, 0 failures, 0 errors, 0 skips")
+  end
+end
diff --git a/features/bundler-app/retest/support/output_file.rb b/features/bundler-app/retest/support/output_file.rb
deleted file mode 100644
index c58f646e..00000000
--- a/features/bundler-app/retest/support/output_file.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-class OutputFile
-  attr_reader :output
-  def initialize
-    @output = Tempfile.new
-  end
-
-  def path
-    @output.path
-  end
-
-  def read
-    @output.rewind
-    @output.read.split('').last
-  end
-
-  def delete
-    @output.close
-    @output.unlink
-  end
-  alias :clear :delete
-end
diff --git a/features/bundler-app/retest/support/test_helper.rb b/features/bundler-app/retest/support/test_helper.rb
index 2b41621f..47ae6a8d 100644
--- a/features/bundler-app/retest/support/test_helper.rb
+++ b/features/bundler-app/retest/support/test_helper.rb
@@ -1,59 +1,101 @@
-require_relative 'output_file'
+# Can be updated to all feature repositories with
+# $ bin/test/reset_helpers
 
-module FileHelper
-  def default_sleep_seconds
-    Float(ENV.fetch('DEFAULT_SLEEP_SECONDS', 1))
+module RetestHelper
+  # COMMAND
+  def launch_retest(command, sleep_seconds: Float(ENV.fetch('LAUNCH_SLEEP_SECONDS', 1.5)))
+    require 'open3'
+    @input, @output, @stderr, @wait_thr = Open3.popen3(command)
+    @pid = @wait_thr[:pid]
+    sleep sleep_seconds
   end
 
-  def launch_sleep_seconds
-    Float(ENV.fetch('LAUNCH_SLEEP_SECONDS', 1.5))
+  def end_retest
+    @input&.close
+    @stderr&.close
+    @output&.close
+    if @pid
+      Process.kill('SIGHUP', @pid)
+      Process.detach(@pid)
+    end
   end
 
-  def wait(sleep_seconds: default_sleep_seconds)
-    sleep sleep_seconds
+  # ASSERTIONS
+  def assert_output_matches(*expectations, max_retries: 5)
+    retries = 0
+    wait_for = 0.1
+    output = ""
+    begin
+      output += read_output
+      expectations.each { |expectation| assert_match(expectation, output) }
+    rescue Minitest::Assertion => e
+      raise e if retries >= max_retries
+      retries += 1
+      sleep_seconds = wait_for ** -(wait_for * retries)
+      sleep sleep_seconds
+      retry
+    end
   end
 
-  def modify_file(path, sleep_seconds: default_sleep_seconds)
+  # OUTPUT
+  def read_output(output = @output)
+    result = ""
+    loop do
+      result += output.read_nonblock(1024)
+    rescue IO::WaitReadable
+      break
+    end
+
+    if block_given?
+      yield result
+    else
+      result
+    end
+  end
+
+  # INPUT
+  def write_input(command, input: @input, sleep_for: 0.1)
+    input.write(command)
+    wait(sleep_for)
+  end
+
+  # FILE CHANGES
+  def modify_file(path, sleep_for: default_sleep_seconds)
     return unless File.exist? path
 
     old_content = File.read(path)
     File.open(path, 'w') { |file| file.write old_content }
-
-    sleep sleep_seconds
+    wait(sleep_for)
   end
 
-  def create_file(path, should_sleep: true, sleep_seconds: default_sleep_seconds)
-    File.open(path, "w").tap(&:close)
-
-    sleep sleep_seconds if should_sleep
+  def create_file(path, content: "", sleep_for: default_sleep_seconds)
+    File.open(path, "w") { |f| f.write(content) }
+    wait(sleep_for)
   end
 
-  def delete_file(path)
+  def delete_file(path, sleep_for: 0)
     return unless File.exist? path
 
     File.delete path
+    wait(sleep_for)
   end
 
-  def rename_file(path, new_path)
+  def rename_file(path, new_path, sleep_for: 0)
     return unless File.exist? path
 
     File.rename path, new_path
+    wait(sleep_for)
   end
-end
 
-def launch_retest(command, sleep_seconds: launch_sleep_seconds)
-  @rd, @input = IO.pipe
-  @output = OutputFile.new
-  @pid = Process.spawn command, out: @output.path, in: @rd
-  sleep sleep_seconds
-end
+  def default_sleep_seconds
+    Float(ENV.fetch('DEFAULT_SLEEP_SECONDS', 1))
+  end
+
+  def launch_sleep_seconds
+    Float(ENV.fetch('LAUNCH_SLEEP_SECONDS', 1.5))
+  end
 
-def end_retest(file = nil, pid = nil)
-  @output&.delete
-  @rd&.close
-  @input&.close
-  if @pid
-    Process.kill('SIGHUP', @pid)
-    Process.detach(@pid)
+  def wait(sleep_for = default_sleep_seconds)
+    sleep sleep_for
   end
 end
diff --git a/features/bundler-app/test/bundler_app/test_fibonacci.rb b/features/bundler-app/test/bundler_app/test_fibonacci.rb
new file mode 100644
index 00000000..28c131c9
--- /dev/null
+++ b/features/bundler-app/test/bundler_app/test_fibonacci.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+module BundlerApp
+  class FibonacciTest < Minitest::Test
+    def test_fibonacci_zero
+      assert_equal 0, Fibonacci.calculate(0)
+    end
+
+    def test_fibonacci_one
+      assert_equal 1, Fibonacci.calculate(1)
+    end
+
+    def test_fibonacci_two
+      assert_equal 1, Fibonacci.calculate(2)
+    end
+
+    def test_fibonacci_five
+      assert_equal 5, Fibonacci.calculate(5)
+    end
+
+    def test_fibonacci_ten
+      assert_equal 55, Fibonacci.calculate(10)
+    end
+
+    def test_large_fibonacci
+      assert_equal 6765, Fibonacci.calculate(20) # Example large Fibonacci number
+    end
+
+    def test_invalid_input_negative
+      assert_raises(ArgumentError) { Fibonacci.calculate(-1) }
+    end
+
+    def test_invalid_input_non_integer
+      assert_raises(ArgumentError) { Fibonacci.calculate(2.5) }
+      assert_raises(ArgumentError) { Fibonacci.calculate("five") }
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/retest/runner.rb b/lib/retest/runner.rb
index aa26f4ab..825e8384 100644
--- a/lib/retest/runner.rb
+++ b/lib/retest/runner.rb
@@ -30,7 +30,8 @@ def run(changed_files: [], test_files: [])
     end
 
     def run_all
-      system_run command.clone(all: true).to_s
+      self.last_command = command.clone(all: true).to_s
+      system_run last_command
     end
 
     def format_instruction(changed_files: [], test_files: [])