Add testing for universe

1 files changed, 146 insertions, 0 deletions

diff --git a/CLI/ruby/spec/game_of_life/universe_spec.rb b/CLI/ruby/spec/game_of_life/universe_spec.rb
new file mode 100644
index 0000000..c8aad02
--- /dev/null
+++ b/CLI/ruby/spec/game_of_life/universe_spec.rb
@@ -0,0 +1,146 @@
+# frozen_string_literal: true
+
+RSpec.describe GameOfLife::Universe do
+  describe ".new" do
+    it "creates a @current 2D array (Plane) of height * width" do
+      universe = described_class.new(width: 10, height: 1)
+      current_generation = universe.instance_variable_get(:@current)
+
+      expect(current_generation).to be_a GameOfLife::Plane
+      expect(current_generation[0]).to be_a GameOfLife::Plane
+
+      expect(current_generation.size).to eq 1
+      expect(current_generation[0].size).to eq 10
+    end
+
+    it "creates a @future 2D array (Plane) of height * width" do
+      universe = described_class.new(width: 10, height: 1)
+      future_generation = universe.instance_variable_get(:@future)
+
+      expect(future_generation).to be_a GameOfLife::Plane
+      expect(future_generation[0]).to be_a GameOfLife::Plane
+
+      expect(future_generation.size).to eq 1
+      expect(future_generation[0].size).to eq 10
+    end
+  end
+
+  describe "#to_s" do
+    subject(:universe) { described_class.new(width: 3, height: 3) }
+
+    before do
+      universe[0] = [1, 2, 3]
+      universe[1] = [4, 5, 6]
+      universe[2] = [7, 8, 9]
+    end
+
+    it "prints out the universe 2D @current array" do
+      expect(universe.to_s).to eq "123\n456\n789"
+    end
+  end
+
+  describe "#evolve!" do
+    subject(:universe) { described_class.new(width: 3, height: 3) }
+
+    before do
+      # quick way to initialize the whole universe with living cells
+      9.times { |i| universe[i / 3][i % 3] = GameOfLife::Cell.new(y: i / 3, x: i % 3, alive: true) }
+    end
+
+    it "calls Cell#evolve! on every cell" do
+      9.times { |i| expect(universe[i / 3][i % 3]).to receive(:evolve!) }
+      universe.evolve!
+    end
+
+    it "updates the universe current state" do
+      9.times { |i| expect(universe[i / 3][i % 3]).to be_alive }
+      universe.evolve!
+      9.times { |i| expect(universe[i / 3][i % 3]).to be_dead }
+    end
+  end
+
+  describe "#neighbors" do
+    subject(:universe) { described_class.new(width: 5, height: 5) }
+
+    it "returns surronding neighbors" do
+      current = GameOfLife::Plane.new(
+        [
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[. x x x .]),
+          GameOfLife::Plane.new(%w[. x C x .]),
+          GameOfLife::Plane.new(%w[. x x x .]),
+          GameOfLife::Plane.new(%w[. . . . .]),
+        ],
+      )
+      universe.instance_variable_set(:@current, current)
+      cell = GameOfLife::Cell.new(y: 2, x: 2, alive: "C")
+
+      expect(universe.send(:neighbors, cell)).to eq %w[x x x x x x x x]
+    end
+
+    it "returns surronding neighbors (beyond top edge)" do
+      current = GameOfLife::Plane.new(
+        [
+          GameOfLife::Plane.new(%w[. x C x .]),
+          GameOfLife::Plane.new(%w[. x x x .]),
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[. x x x .]),
+        ],
+      )
+      universe.instance_variable_set(:@current, current)
+      cell = GameOfLife::Cell.new(y: 0, x: 2, alive: "C")
+
+      expect(universe.send(:neighbors, cell)).to eq %w[x x x x x x x x]
+    end
+
+    it "returns surronding neighbors (beyond left edge)" do
+      current = GameOfLife::Plane.new(
+        [
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[x x . . x]),
+          GameOfLife::Plane.new(%w[C x . . x]),
+          GameOfLife::Plane.new(%w[x x . . x]),
+        ],
+      )
+      universe.instance_variable_set(:@current, current)
+      cell = GameOfLife::Cell.new(y: 3, x: 0, alive: "C")
+
+      expect(universe.send(:neighbors, cell)).to eq %w[x x x x x x x x]
+    end
+
+    it "returns surronding neighbors (beyond diagonal edges)" do
+      current = GameOfLife::Plane.new(
+        [
+          GameOfLife::Plane.new(%w[C x . . x]),
+          GameOfLife::Plane.new(%w[x x . . x]),
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[x x . . x]),
+        ],
+      )
+      universe.instance_variable_set(:@current, current)
+      cell = GameOfLife::Cell.new(y: 0, x: 0, alive: "C")
+
+      expect(universe.send(:neighbors, cell)).to eq %w[x x x x x x x x]
+    end
+
+    it "returns surronding neighbors (beyond reversed diagonal edges)" do
+      current = GameOfLife::Plane.new(
+        [
+          GameOfLife::Plane.new(%w[x . . x x]),
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[. . . . .]),
+          GameOfLife::Plane.new(%w[x . . x x]),
+          GameOfLife::Plane.new(%w[x . . x C]),
+        ],
+      )
+
+      universe.instance_variable_set(:@current, current)
+      cell = GameOfLife::Cell.new(y: 4, x: 4, alive: "C")
+
+      expect(universe.send(:neighbors, cell)).to eq %w[x x x x x x x x]
+    end
+  end
+end