Add examples

Author: mrkn

spec/enum/sample_spec.rb

@@ -5,6 +5,107 @@
   let(:random) { Random.new }
   let(:n) { 20 }
 
+  let(:replace) { nil }
+  let(:weights) { nil }
+  let(:opts) { {} }
+
+  before do
+    opts[:replace] = replace if replace
+    opts[:weights] = weights if weights
+  end
+
+  context 'when the receiver has 1 item' do
+    let(:enum) { 1.upto(1) }
+
+    shared_examples_for '1-item enumerable' do
+      context 'without replacement' do
+        specify { expect(opts).not_to include(:replace) }
+
+        specify do
+          expect(enum.sample(**opts)).to eq(1)
+
+          expect(enum.sample(10, **opts)).to eq([1])
+          expect(enum.sample(20, **opts)).to eq([1])
+        end
+      end
+
+      context 'with replacement' do
+        let(:replace) { true }
+
+        specify { expect(opts).to include(replace: true) }
+
+        specify do
+          expect(enum.sample(10, **opts)).to eq(Array.new(10, 1))
+          expect(enum.sample(20, **opts)).to eq(Array.new(20, 1))
+        end
+      end
+    end
+
+    context 'without weights' do
+      specify { expect(opts).not_to include(:weights) }
+
+      include_examples '1-item enumerable'
+    end
+
+    # TODO: weights
+    xcontext 'with weights' do
+      let(:weights) do
+        { 1 => 1.0 }
+      end
+
+      specify { expect(opts).to include(weights: weights) }
+
+      include_examples '1-item enumerable'
+    end
+  end
+
+  context 'when the receiver has 2 item' do
+    let(:enum) { 1.upto(2) }
+
+    shared_examples_for 'sample from 2-item enumerable without replacement' do
+      specify { expect(opts).not_to include(:replace) }
+
+      specify do
+        expect(Array.new(100) { enum.sample(**opts) }).to all(eq(1).or eq(2))
+
+        expect(enum.sample(10, **opts)).to contain_exactly(1, 2)
+        expect(enum.sample(20, **opts)).to contain_exactly(1, 2)
+      end
+    end
+
+    context 'without weights' do
+      context 'without replacement' do
+        it_behaves_like 'sample from 2-item enumerable without replacement'
+      end
+
+      context 'with replacement' do
+        let(:replace) { true }
+
+        specify { expect(opts).to include(replace: true) }
+
+        specify do
+          expect(enum.sample(10, **opts)).to have_attributes(length: 10).and all(eq(1).or eq(2))
+          expect(enum.sample(20, **opts)).to have_attributes(length: 20).and all(eq(1).or eq(2))
+        end
+      end
+    end
+
+    # TODO: weights
+    xcontext 'with weights' do
+      specify { expect(opts).to include(weights: weights) }
+
+      context 'without replacement' do
+        it_behaves_like 'sample from 2-item enumerable without replacement'
+      end
+
+      context 'with replacement' do
+        let(:replace) { true }
+
+        specify { expect(opts).to include(replace: true) }
+      end
+    end
+  end
+
   context 'without weight' do
     let(:enum) { 1.upto(100000) }
 
@@ -65,7 +166,7 @@
             expect(result.length).to eq(n)
             expect(result.uniq.length).to eq(n)
             other_results = Array.new(100) { enum.sample(n) }
-	    expect(other_results).not_to be_all {|i| i == result }
+            expect(other_results).not_to be_all {|i| i == result }
           end
         end
 
@@ -79,7 +180,7 @@
             expect(result.length).to eq(n)
             expect(result.uniq.length).to eq(n)
             other_results = Array.new(100) { enum.sample(n, random: save_random.dup) }
-	    expect(other_results).to be_all {|i| i == result }
+            expect(other_results).to be_all {|i| i == result }
           end
         end
       end