Add tests for `Retrospring::Version`

spec/lib/version_spec.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "version"
+
+RSpec.describe Retrospring::Version do
+  before(:each) do
+    allow(Retrospring::Version).to receive(:year) { 1984 }
+    allow(Retrospring::Version).to receive(:month) { 1 }
+    allow(Retrospring::Version).to receive(:day) { 1 }
+    allow(Retrospring::Version).to receive(:patch) { 0 }
+  end
+
+  describe "#to_s" do
+    context "without suffix" do
+      it "should return the correct version string" do
+        expect(Retrospring::Version.to_s).to eq("1984.0101.0")
+      end
+    end
+
+    context "with suffix" do
+      before(:each) do
+        allow(Retrospring::Version).to receive(:suffix) { "+shutdown" }
+      end
+
+      it "should return the correct version string" do
+        expect(Retrospring::Version.to_s).to eq("1984.0101.0+shutdown")
+      end
+    end
+  end
+
+  describe "#to_a" do
+    it "should return the correct version as array" do
+      expect(Retrospring::Version.to_a).to eq(["1984", "0101", "0"])
+    end
+  end
+end