Add performance tests

Gemfile

@@ -13,6 +13,10 @@ if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.4.0")
   gem "listen", "3.0.8"
 end
 
+if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new("2.1.0")
+  gem "rspec-benchmark", "~> 0.6"
+end
+
 if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new("2.5.0")
   gem "coveralls_reborn", "~> 0.24.0"
   gem "simplecov", "~> 0.21.0"

spec/perf/runner_spec.rb

@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+require "rspec-benchmark"
+require "tempfile"
+
+RSpec.describe Slideck::Runner, "#run" do
+  include RSpec::Benchmark::Matchers
+
+  let(:input) { StringIO.new("".dup, "w+") }
+  let(:output) { StringIO.new("".dup, "w+") }
+  let(:env) { {"TTY_TEST" => true} }
+
+  it "runs a presentation with 100 slides at 200 i/s" do
+    metadata = "align: center\nmargin: 1 2\nsymbols: ascii\n"
+    slides = Array.new(100) { |i| "---\nSlide#{i}" }.join("\n")
+    runner = described_class.new(TTY::Screen, input, output, env)
+
+    Tempfile.create("slides.md") do |file|
+      file << metadata
+      file << slides
+      input << "q"
+
+      expect {
+        file.rewind
+        input.rewind
+        runner.run(file.path, color: :always, watch: false)
+      }.to perform_at_least(200).ips
+    end
+  end
+
+  it "runs a presentation with no slides allocating 557 objects" do
+    runner = described_class.new(TTY::Screen, input, output, env)
+    file_path = fixtures_path("empty.md")
+    input << "q"
+
+    expect {
+      input.rewind
+      runner.run(file_path, color: :always, watch: false)
+    }.to perform_allocation(557).objects
+  end
+
+  it "runs a presentation with 100 slides allocating 2.5K objects" do
+    metadata = "align: center\nmargin: 1 2\nsymbols: ascii\n"
+    slides = Array.new(100) { |i| "---\nSlide#{i}" }.join("\n")
+    runner = described_class.new(TTY::Screen, input, output, env)
+
+    Tempfile.create("slides.md") do |file|
+      file << metadata
+      file << slides
+      input << "q"
+
+      expect {
+        file.rewind
+        input.rewind
+        runner.run(file.path, color: :always, watch: false)
+      }.to perform_allocation(2555).objects
+    end
+  end
+
+  it "runs presentations with increasing slides sizes in linear time" do
+    sizes = bench_range(8, 10_000)
+    metadata = "align: center\nmargin: 1 2\nsymbols: ascii\n"
+    slides = sizes.map { |n| Array.new(n) { |i| "---\nSlide#{i}" }.join("\n") }
+    runner = described_class.new(TTY::Screen, input, output, env)
+
+    Tempfile.create("slides.md") do |file|
+      input << "q"
+
+      expect { |_, i|
+        file.rewind
+        file << metadata
+        file << slides[i]
+        file.rewind
+        input.rewind
+        runner.run(file.path, color: :always, watch: false)
+      }.to perform_linear.in_range(sizes)
+    end
+  end
+end