diff --git a/spec/unit/generator/generator_tags_spec.rb b/spec/unit/generator/generator_tags_spec.rb
index ebcd866..5e6b442 100644
--- a/spec/unit/generator/generator_tags_spec.rb
+++ b/spec/unit/generator/generator_tags_spec.rb
@@ -1,21 +1,21 @@
 describe GitHubChangelogGenerator::Generator do
   describe "#get_filtered_tags" do
-    before(:all) do
-      @generator = GitHubChangelogGenerator::Generator.new
-    end
-
     context "when between_tags nil" do
+      before do
+        @generator = GitHubChangelogGenerator::Generator.new(between_tags: nil)
+      end
+
       subject do
-        @generator.instance_variable_set("@options", between_tags: nil)
         @generator.get_filtered_tags(%w(1 2 3))
       end
       it { is_expected.to be_a(Array) }
       it { is_expected.to match_array(%w(1 2 3)) }
     end
-
     context "when between_tags same as input array" do
+      before do
+        @generator = GitHubChangelogGenerator::Generator.new(between_tags: %w(1 2 3))
+      end
       subject do
-        @generator.instance_variable_set("@options", between_tags: %w(1 2 3))
         @generator.get_filtered_tags(%w(1 2 3))
       end
       it { is_expected.to be_a(Array) }
@@ -23,16 +23,22 @@ describe GitHubChangelogGenerator::Generator do
     end
 
     context "when between_tags filled with correct values" do
+      before do
+        @generator = GitHubChangelogGenerator::Generator.new(between_tags: %w(1 2))
+      end
       subject do
-        @generator.instance_variable_set("@options", between_tags: %w(1 2))
         @generator.get_filtered_tags(%w(1 2 3))
       end
       it { is_expected.to be_a(Array) }
       it { is_expected.to match_array(%w(1 2)) }
     end
+
     context "when between_tags filled with invalid values" do
+      before do
+        @generator = GitHubChangelogGenerator::Generator.new(between_tags: %w(1 q w))
+      end
+
       subject do
-        @generator.instance_variable_set("@options", between_tags: %w(1 q w))
         @generator.get_filtered_tags(%w(1 2 3))
       end
       it { is_expected.to be_a(Array) }