add tests

spec/unit/generator/generator_tags_spec.rb

@@ -0,0 +1,29 @@
+describe GitHubChangelogGenerator::Generator do
+  describe "#get_filtered_tags" do
+    before(:all) do
+      @generator = GitHubChangelogGenerator::Generator.new
+    end
+
+    context "when between_tags nil" do
+      # before(:each) do
+      #   @generator.options = {}
+      # end
+      subject { @generator.get_filtered_tags(%w(1 2 3)) }
+      it { is_expected.to be_a(Array) }
+      it { is_expected.to match_array(%w(1 2 3)) }
+    end
+
+    context "when between_tags 1" do
+      # before(:each) do
+      #   @generator.options = {between_tags: ["1"]}
+      # end
+
+      subject do
+        @generator.instance_variable_set("@options", between_tags: ["1"])
+        @generator.get_filtered_tags(%w(1 2 3))
+      end
+      it { is_expected.to be_a(Array) }
+      it { is_expected.to match_array(%w(1)) }
+    end
+  end
+end