diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 98714b8..761a986 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -201,7 +201,11 @@ RSpec/SpecFilePathFormat:
     - 'spec/ruby-link-checker/callbacks_spec.rb'
     - 'spec/ruby-link-checker/checker_spec.rb'
     - 'spec/ruby-link-checker/config_spec.rb'
+    - 'spec/ruby-link-checker/errors/redirect_loop_error_spec.rb'
     - 'spec/ruby-link-checker/net/http/checker_spec.rb'
+    - 'spec/ruby-link-checker/result_error_spec.rb'
+    - 'spec/ruby-link-checker/result_spec.rb'
+    - 'spec/ruby-link-checker/task_spec.rb'
     - 'spec/ruby-link-checker/tasks_spec.rb'
     - 'spec/ruby-link-checker/typhoeus/hydra/checker_spec.rb'
     - 'spec/ruby-link-checker/version_spec.rb'
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7c56200..bace02e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 * [#19](https://github.com/dblock/ruby-link-checker/pull/19): Added `LinkChecker::Async::HTTP`, a link checker based on [async-http](https://github.com/socketry/async-http) - [@dblock](https://github.com/dblock), [@Copilot](https://github.com/Copilot).
 * [#19](https://github.com/dblock/ruby-link-checker/pull/19): Dropped support for Ruby < 3.3 - [@dblock](https://github.com/dblock), [@Copilot](https://github.com/Copilot).
 * [#20](https://github.com/dblock/ruby-link-checker/pull/20): Added support for custom headers - [@dblock](https://github.com/dblock), [@Copilot](https://github.com/Copilot).
+* [#21](https://github.com/dblock/ruby-link-checker/pull/21): Improved test coverage to 100% and fixed Danger dry_run failure by unpinning `danger-changelog` - [@dblock](https://github.com/dblock), [@Copilot](https://github.com/Copilot).
 * Your contribution here.
 
 ### 0.3.0 (2025-07-05)
diff --git a/Gemfile b/Gemfile
index ee2e76c..a415ca3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rake'
 
 group :development, :test do
   gem 'danger'
-  gem 'danger-changelog', '0.6.1'
+  gem 'danger-changelog', '0.8.0'
   gem 'danger-pr-comment'
   gem 'danger-toc', '0.2.0'
   gem 'rspec', '~> 3.0'
diff --git a/spec/ruby-link-checker/async/http/checker_spec.rb b/spec/ruby-link-checker/async/http/checker_spec.rb
index 04db2d7..8b06f02 100644
--- a/spec/ruby-link-checker/async/http/checker_spec.rb
+++ b/spec/ruby-link-checker/async/http/checker_spec.rb
@@ -35,6 +35,12 @@ def check(url, options = {})
   describe AsyncTestLinkChecker::LinkChecker do
     it_behaves_like 'a link checker'
 
+    describe '.config' do
+      it 'returns the Config module' do
+        expect(LinkChecker::Async::HTTP.config).to eq LinkChecker::Async::HTTP::Config
+      end
+    end
+
     context 'with timeout options', vcr: { cassette_name: '200' } do
       before do
         LinkChecker::Async::HTTP.configure do |config|
@@ -80,4 +86,14 @@ def check(url, options = {})
       end
     end
   end
+
+  describe LinkChecker::Async::HTTP::Result do
+    describe '#code' do
+      it 'returns -1 when there is no response' do
+        request = instance_double(Protocol::HTTP::Request)
+        result = described_class.new(URI('https://www.example.org'), 'GET', nil, request, nil, {})
+        expect(result.code).to eq(-1)
+      end
+    end
+  end
 end
diff --git a/spec/ruby-link-checker/callbacks_spec.rb b/spec/ruby-link-checker/callbacks_spec.rb
index 41047be..c861668 100644
--- a/spec/ruby-link-checker/callbacks_spec.rb
+++ b/spec/ruby-link-checker/callbacks_spec.rb
@@ -6,6 +6,10 @@
   subject do
     Class.new do
       include LinkChecker::Callbacks
+
+      def logger
+        @logger ||= Logger.new(nil)
+      end
     end.new
   end
 
@@ -40,4 +44,33 @@
       expect(subject).to have_received(:called!).with(:bar)
     end
   end
+
+  context 'method_missing' do
+    it 'invokes callback for a bang method' do
+      allow(subject).to receive(:called!)
+      subject.on :foo do |data|
+        subject.called! data
+      end
+      subject.foo! :foo
+      expect(subject).to have_received(:called!).with(:foo)
+    end
+
+    it 'raises NoMethodError for a non-bang method' do
+      expect { subject.foo }.to raise_error NoMethodError
+    end
+  end
+
+  context 'when a callback raises an error' do
+    before do
+      subject.on :foo do
+        raise StandardError, 'oops'
+      end
+    end
+
+    it 'rescues and logs the error' do
+      allow(subject.logger).to receive(:error)
+      expect(subject.send(:callback, :foo)).to be false
+      expect(subject.logger).to have_received(:error)
+    end
+  end
 end
diff --git a/spec/ruby-link-checker/errors/redirect_loop_error_spec.rb b/spec/ruby-link-checker/errors/redirect_loop_error_spec.rb
new file mode 100644
index 0000000..33132e5
--- /dev/null
+++ b/spec/ruby-link-checker/errors/redirect_loop_error_spec.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe LinkChecker::Errors::RedirectLoopError do
+  subject(:error) do
+    described_class.new(['https://www.example.org', 'https://www.example.org/redirect'])
+  end
+
+  it 'returns the last url' do
+    expect(error.url).to eq 'https://www.example.org/redirect'
+  end
+
+  it 'formats a message with all urls' do
+    expect(error.message)
+      .to eq 'Redirect loop: https://www.example.org -> https://www.example.org/redirect.'
+  end
+end
diff --git a/spec/ruby-link-checker/net/http/checker_spec.rb b/spec/ruby-link-checker/net/http/checker_spec.rb
index 04f44b6..cb2faeb 100644
--- a/spec/ruby-link-checker/net/http/checker_spec.rb
+++ b/spec/ruby-link-checker/net/http/checker_spec.rb
@@ -15,6 +15,12 @@
 
   it_behaves_like 'a link checker'
 
+  describe '.config' do
+    it 'returns the Config module' do
+      expect(LinkChecker::Net::HTTP.config).to eq LinkChecker::Net::HTTP::Config
+    end
+  end
+
   context 'with timeout options', vcr: { cassette_name: '200' } do
     before do
       LinkChecker::Net::HTTP.configure do |config|
@@ -58,4 +64,15 @@
       end
     end
   end
+
+  describe LinkChecker::Net::HTTP::Result do
+    describe '#code' do
+      it 'returns -1 when the response raises' do
+        response = instance_double(Net::HTTPResponse)
+        allow(response).to receive(:code).and_raise(StandardError)
+        result = described_class.new(URI('https://www.example.org'), 'GET', nil, nil, response, {})
+        expect(result.code).to eq(-1)
+      end
+    end
+  end
 end
diff --git a/spec/ruby-link-checker/result_error_spec.rb b/spec/ruby-link-checker/result_error_spec.rb
new file mode 100644
index 0000000..44d4897
--- /dev/null
+++ b/spec/ruby-link-checker/result_error_spec.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe LinkChecker::ResultError do
+  subject(:result) do
+    described_class.new('https://www.example.org', 'GET', 'https://www.example.org', StandardError.new('oops'))
+  end
+
+  it 'is an error' do
+    expect(result.error?).to be true
+  end
+
+  it 'returns the error class name as code' do
+    expect(result.code).to eq 'StandardError'
+  end
+end
diff --git a/spec/ruby-link-checker/result_spec.rb b/spec/ruby-link-checker/result_spec.rb
new file mode 100644
index 0000000..9001584
--- /dev/null
+++ b/spec/ruby-link-checker/result_spec.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe LinkChecker::Result do
+  subject(:result) do
+    described_class.new('https://www.example.org', 'GET', 'https://www.example.org')
+  end
+
+  it 'defaults to not successful' do
+    expect(result.success?).to be false
+  end
+
+  it 'defaults to not a failure' do
+    expect(result.failure?).to be false
+  end
+
+  it 'defaults to not an error' do
+    expect(result.error?).to be false
+  end
+
+  it 'defaults to not a redirect' do
+    expect(result.redirect?).to be false
+  end
+
+  it 'defaults redirect_to to nil' do
+    expect(result.redirect_to).to be_nil
+  end
+
+  it 'defaults request_headers to an empty hash' do
+    expect(result.request_headers).to eq({})
+  end
+
+  it 'defaults code to nil' do
+    expect(result.code).to be_nil
+  end
+
+  it 'defaults error to nil' do
+    expect(result.error).to be_nil
+  end
+end
diff --git a/spec/ruby-link-checker/task_spec.rb b/spec/ruby-link-checker/task_spec.rb
new file mode 100644
index 0000000..d8e6806
--- /dev/null
+++ b/spec/ruby-link-checker/task_spec.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe LinkChecker::Task do
+  subject(:task) do
+    described_class.new(
+      LinkChecker::Net::HTTP::Checker.new,
+      'https://www.example.org',
+      'GET',
+      'https://www.example.org'
+    )
+  end
+
+  describe '#run!' do
+    it 'raises NotImplementedError' do
+      expect { task.run! }.to raise_error NotImplementedError
+    end
+  end
+end
diff --git a/spec/ruby-link-checker/tasks_spec.rb b/spec/ruby-link-checker/tasks_spec.rb
index 3de3dca..fbec879 100644
--- a/spec/ruby-link-checker/tasks_spec.rb
+++ b/spec/ruby-link-checker/tasks_spec.rb
@@ -33,4 +33,15 @@
       end
     end
   end
+
+  describe '#retries' do
+    let(:checker) { LinkChecker::Net::HTTP::Checker.new(methods: ['GET'], retries: 2) }
+    let(:task_klass) { LinkChecker::Net::HTTP::Task }
+    let(:url) { 'https://www.example.org' }
+
+    it 'delegates to the checker' do
+      tasks = described_class.new(checker, task_klass, url, ['GET'])
+      expect(tasks.send(:retries)).to eq 2
+    end
+  end
 end
diff --git a/spec/ruby-link-checker/typhoeus/hydra/checker_spec.rb b/spec/ruby-link-checker/typhoeus/hydra/checker_spec.rb
index 7baa9e4..025a35b 100644
--- a/spec/ruby-link-checker/typhoeus/hydra/checker_spec.rb
+++ b/spec/ruby-link-checker/typhoeus/hydra/checker_spec.rb
@@ -22,6 +22,12 @@ def check(url, options = {})
   describe TyphoeusTestLinkChecker::LinkChecker do
     it_behaves_like 'a link checker'
 
+    describe '.config' do
+      it 'returns the Config module' do
+        expect(LinkChecker::Typhoeus::Hydra.config).to eq LinkChecker::Typhoeus::Hydra::Config
+      end
+    end
+
     context 'with timeout options', vcr: { cassette_name: '200' } do
       before do
         LinkChecker::Typhoeus::Hydra.configure do |config|
@@ -64,4 +70,24 @@ def check(url, options = {})
       end
     end
   end
+
+  describe LinkChecker::Typhoeus::Hydra::Result do
+    describe '#code' do
+      it 'returns -1 when the response raises' do
+        request = instance_double(Typhoeus::Request)
+        response = instance_double(Typhoeus::Response)
+        allow(response).to receive(:code).and_raise(StandardError)
+        result = described_class.new(URI('https://www.example.org'), 'GET', nil, request, response, {})
+        expect(result.code).to eq(-1)
+      end
+    end
+  end
+
+  describe '#run' do
+    it 'delegates to the hydra' do
+      checker = described_class.new
+      expect(checker.instance_variable_get(:@hydra)).to receive(:run)
+      checker.run
+    end
+  end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 0c5eb57..4a5d139 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -5,7 +5,9 @@
 require 'rubygems'
 
 require 'simplecov'
-SimpleCov.start
+SimpleCov.start do
+  add_filter '/spec/'
+end
 
 require 'rspec'
 require 'ruby-link-checker'