Cleaning up and writing tests

game/spec/universe_spec.rb

@@ -0,0 +1,146 @@
+# frozen_string_literal: true
+
+require './universe'
+require './planet'
+require './position'
+require './universe_array'
+
+require './spec/stdout_helper'
+
+RSpec.describe Universe do
+
+  let(:name)          { 'Test Universe' }
+  let(:universe_size) { 3 }
+  let(:seed)          { 12345 }
+
+  subject(:universe) do
+    Universe.new(
+      name,
+      universe_size: universe_size,
+      seed:          seed,
+      create_chances: { planet: 1 }   # force a planet at every valid spot
+    )
+  end
+
+  describe '#initialize' do
+    it 'stores all expected instance variables' do
+      expect(universe.name).to eq(name)
+      expect(universe.instance_variable_get(:@universe_size)).to eq(universe_size)
+      expect(universe.instance_variable_get(:@seed)).to eq(seed)
+    end
+
+    it 'creates a deterministic Random object when a seed is given' do
+      rng = universe.instance_variable_get(:@random)
+      expect(rng).to be_a(Random)
+      expect(rng.rand(100)).to eq(Random.new(seed).rand(100))
+    end
+
+    it 'initializes the random if no seed is passed in' do
+      uni = Universe.new(name)
+      rng = uni.instance_variable_get(:@random)
+      expect(rng).to be_a(Random)
+    end
+  end
+
+  describe '#create_universe' do
+
+  end
+
+  describe '#distance' do
+    it 'is symmetric' do
+      a = Position.new(0, 0)
+      b = Position.new(4, 2)
+      expect(universe.distance(a, b)).to eq(universe.distance(b, a))
+    end
+
+    it 'returns 0 when both points are identical' do
+      p = Position.new(1, 1)
+      expect(universe.distance(p, p)).to eq(0)
+    end
+
+    it 'correctly computes known hex distances' do
+      p0 = Position.new(0, 0)
+      p1 = Position.new(2, 0)
+      p2 = Position.new(4, 2)
+      p3 = Position.new(2, 2)
+      # (0,0) to (2,0)  → 1
+      expect(universe.distance(p0, p1)).to eq(1)
+      # (0,0) to (4,2)  → 3
+      expect(universe.distance(p0, p2)).to eq(3)
+      # (0,0) to (2,2)  → 2
+      expect(universe.distance(p0, p3)).to eq(2)
+    end
+  end
+
+  describe '#map generation' do
+    it 'creates the expected dimensions' do
+      universe.create_universe
+      map = universe.instance_variable_get(:@universe_map)
+      # Each valid (x,y) pair inside the radius contains a Planet
+      # (our stub) and every other entry is nil.
+      expect(map).to be_a(UniverseArray)
+      # Check how may nodes were created:
+      expect(map.flatten.compact.length).to eq(19) # 1 + 1*6 + 2*6
+    end
+
+    it 'contains a planet at every valid point when create_chances is 1' do
+      universe.create_universe
+      map = universe.instance_variable_get(:@universe_map)
+      map.each do |row|
+        row.each do |idx|
+          # The indexes are allowed to be nil
+          if !idx.nil?
+            expect(idx).to be_a(Planet)
+          end
+        end
+      end
+    end
+
+    it 'is deterministic when the same seed is used' do
+      first_universe = Universe.new(
+        name,
+        universe_size: universe_size,
+        seed:          seed,
+        create_chances: { planet: 0.1 }
+      )
+      first_map = first_universe.instance_variable_get(:@universe_map)
+
+      second_universe = Universe.new(
+        name,
+        universe_size: universe_size,
+        seed:          seed,
+        create_chances: { planet: 0.1 }
+      )
+      second_map = second_universe.instance_variable_get(:@universe_map)
+
+      expect(first_map).to eq(second_map)
+    end
+  end
+
+  describe '#print_universe' do
+    it 'prints the center point as “O”' do
+      out = capture_stdout do
+        universe.create_universe
+        universe.print_universe
+      end
+      expect(out).to include('O')
+    end
+
+    it 'can print blank spaces for nothing' do
+      out = capture_stdout do
+        uni = Universe.new(name, create_chances: {planet: 0.0})
+        uni.create_universe
+        uni.print_universe
+      end
+      expect(out).to include('O')
+      expect(out).to include('- -')
+    end
+  end
+
+  describe '#planets' do
+    it 'lists all of the generated planets' do
+      universe.create_universe
+      expect(universe.planets.length).to eq(19)
+    end
+  end
+end