diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a520758..57dce2e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -21,7 +21,7 @@ jobs:
         working-directory: test
       - run: test/await_healthy.sh
       - uses: ./
-        name: Run test
+        name: Run smoke-test (running the action)
         with:
           GL_SERVER_URL: http://172.17.0.1:8080
           GL_PROJECT_ID: '1000'
@@ -32,6 +32,10 @@ jobs:
           GLPA_SOME_VARIABLE: some value for the variable
       - run: 'curl --silent --header "Private-Token: TEST1234567890123456" "http://127.17.0.1:8080/api/v4/projects/1000/jobs/1/trace"'
         if: always()
+      - uses: ruby/setup-ruby@v1
+      - run: bundle install
+      - run: bundle exec rspec
+        name: Run tests (running rspec)
       - run: docker compose down
         if: always()
         working-directory: test
diff --git a/.rubocop.yml b/.rubocop.yml
index f0b527c..9443c5b 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,3 +1,6 @@
+require:
+  - rubocop-rspec
+
 AllCops:
   NewCops: enable
 
@@ -13,6 +16,17 @@ Naming/BlockForwarding:
 Naming/MethodParameterName:
   Enabled: false
 
+RSpec/ExampleLength:
+  Enabled: false
+
+# the action folder does not match gitlab_pipeline_action
+RSpec/FilePath:
+  Enabled: false
+
+# the action folder does not match gitlab_pipeline_action
+RSpec/SpecFilePathFormat:
+  Enabled: false
+
 Style/Documentation:
   Enabled: false
 
diff --git a/Gemfile b/Gemfile
index b208a48..7dca5a6 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,6 +6,12 @@ gem 'gitlab', '~> 4.19'
 
 gem 'git', '~> 1.18'
 
-gem 'rubocop', '~> 1.57'
-
 gem 'docker-api', '~> 2.2'
+
+group :development, :test do
+  gem 'rubocop', '~> 1.57'
+
+  gem 'rubocop-rspec', '~> 2.25'
+
+  gem 'rspec', '~> 3.12'
+end
diff --git a/Gemfile.lock b/Gemfile.lock
index 288feb6..c475371 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -4,6 +4,7 @@ GEM
     addressable (2.8.5)
       public_suffix (>= 2.0.2, < 6.0)
     ast (2.4.2)
+    diff-lcs (1.5.0)
     docker-api (2.2.0)
       excon (>= 0.47.0)
       multi_json
@@ -32,6 +33,19 @@ GEM
     rchardet (1.8.0)
     regexp_parser (2.8.2)
     rexml (3.2.6)
+    rspec (3.12.0)
+      rspec-core (~> 3.12.0)
+      rspec-expectations (~> 3.12.0)
+      rspec-mocks (~> 3.12.0)
+    rspec-core (3.12.2)
+      rspec-support (~> 3.12.0)
+    rspec-expectations (3.12.3)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.12.0)
+    rspec-mocks (3.12.6)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.12.0)
+    rspec-support (3.12.1)
     rubocop (1.57.2)
       json (~> 2.3)
       language_server-protocol (>= 3.17.0)
@@ -45,6 +59,14 @@ GEM
       unicode-display_width (>= 2.4.0, < 3.0)
     rubocop-ast (1.30.0)
       parser (>= 3.2.1.0)
+    rubocop-capybara (2.19.0)
+      rubocop (~> 1.41)
+    rubocop-factory_bot (2.24.0)
+      rubocop (~> 1.33)
+    rubocop-rspec (2.25.0)
+      rubocop (~> 1.40)
+      rubocop-capybara (~> 2.17)
+      rubocop-factory_bot (~> 2.22)
     ruby-progressbar (1.13.0)
     terminal-table (3.0.2)
       unicode-display_width (>= 1.1.1, < 3)
@@ -57,7 +79,9 @@ DEPENDENCIES
   docker-api (~> 2.2)
   git (~> 1.18)
   gitlab (~> 4.19)
+  rspec (~> 3.12)
   rubocop (~> 1.57)
+  rubocop-rspec (~> 2.25)
 
 BUNDLED WITH
    2.4.12
diff --git a/lib/action/context.rb b/lib/action/context.rb
index 472d29e..52374d1 100644
--- a/lib/action/context.rb
+++ b/lib/action/context.rb
@@ -3,7 +3,7 @@
 module GitlabPipelineAction
   class Context
     attr_accessor :gh_project, :gh_sha, :gh_ref, :gh_server_url,
-                  :gl_server_url, :gl_project_id, :gl_project_path, :gl_runner_token,
+                  :gl_server_url, :gl_server_url_for_runner, :gl_project_id, :gl_project_path, :gl_runner_token,
                   :gl_api_token, :gl_pipeline, :gl_branch_name, :gl_pipeline_variables,
                   :gl_show_job_logs,
                   :git_repository, :git_path,
diff --git a/lib/action/entrypoint.rb b/lib/action/entrypoint.rb
index d71d6b4..bec8bb2 100644
--- a/lib/action/entrypoint.rb
+++ b/lib/action/entrypoint.rb
@@ -15,8 +15,7 @@ class Entrypoint
       GitlabPipelineAction::Step::ShowJobLogs
     ].freeze
 
-    def execute
-      context = Context.new
+    def execute(context = Context.new)
       STEPS.each do |step_class|
         step = step_class.new(context)
         print "#{step_class}: "
diff --git a/lib/action/step/prepare_context.rb b/lib/action/step/prepare_context.rb
index 45d6bcd..12f3c96 100644
--- a/lib/action/step/prepare_context.rb
+++ b/lib/action/step/prepare_context.rb
@@ -12,6 +12,10 @@ def execute
         context.gl_branch_name = "glpa/#{ENV.fetch('GITHUB_REF_NAME', nil)}"
 
         context.gl_server_url = ENV.fetch('INPUT_GL_SERVER_URL', nil)
+        context.gl_server_url_for_runner = ENV.fetch(
+          'INPUT_GL_SERVER_URL_FOR_RUNNER', # intentionally undocumented
+          context.gl_server_url
+        )
         context.gl_project_id = ENV.fetch('INPUT_GL_PROJECT_ID', nil)
         context.gl_runner_token = ENV.fetch('INPUT_GL_RUNNER_TOKEN', nil)
         context.gl_api_token = ENV.fetch('INPUT_GL_API_TOKEN', nil)
diff --git a/lib/action/step/start_runner.rb b/lib/action/step/start_runner.rb
index fa7f5e3..692fb17 100644
--- a/lib/action/step/start_runner.rb
+++ b/lib/action/step/start_runner.rb
@@ -20,7 +20,7 @@ def execute
         container.exec([
                          'gitlab-runner', 'register',
                          '--non-interactive',
-                         '--url', context.gl_server_url,
+                         '--url', context.gl_server_url_for_runner,
                          '--token', context.gl_runner_token,
                          '--executor', 'docker',
                          '--docker-image', 'alpine:latest'
diff --git a/spec/action/full_run_spec.rb b/spec/action/full_run_spec.rb
new file mode 100644
index 0000000..23927d4
--- /dev/null
+++ b/spec/action/full_run_spec.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Full run', :require_gitlab do # rubocop:disable RSpec/DescribeClass
+  subject(:execute) { GitlabPipelineAction::Entrypoint.new.execute(context) }
+
+  let(:context) { GitlabPipelineAction::Context.new }
+
+  it 'runs without error', :disable_console do
+    expect { execute }.not_to raise_error
+  end
+
+  it 'does not output job traces by default' do
+    expect { execute }.to output(include('GitlabPipelineAction::Step::ShowJobLogs: skipped')).to_stdout
+  end
+
+  context 'when SHOW_JOB_LOGS is set to failures' do
+    stub_env('INPUT_SHOW_JOB_LOGS', 'failures')
+
+    it 'only outputs job traces of failed jobs' do
+      expect { execute }.to output(
+        include("'failing-job' in stage 'test' (failed)")
+          .and(not_include("'job' in stage 'test' (success)"))
+      ).to_stdout
+    end
+  end
+
+  context 'when SHOW_JOB_LOGS is set to all' do
+    stub_env('INPUT_SHOW_JOB_LOGS', 'all')
+
+    it 'outputs job traces of all jobs' do
+      expect { execute }.to output(
+        include(
+          "'failing-job' in stage 'test' (failed)",
+          "'job' in stage 'test' (success)",
+          "'job-with-commands' in stage 'test' (success)"
+        )
+      ).to_stdout
+    end
+  end
+
+  context 'when setting a variable for the pipeline' do
+    stub_env('GLPA_SOME_VARIABLE', 'A test value for the variable')
+    stub_env('INPUT_SHOW_JOB_LOGS', 'all')
+
+    it 'passes the variable to the pipeline' do
+      expect { execute }.to output(
+        include('A test value for the variable')
+      ).to_stdout
+    end
+  end
+end
diff --git a/spec/action/helper/github_spec.rb b/spec/action/helper/github_spec.rb
new file mode 100644
index 0000000..d7857aa
--- /dev/null
+++ b/spec/action/helper/github_spec.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe GitlabPipelineAction::Helper::Github do
+  it '#warning writes the correct format' do
+    expect do
+      described_class.warning('Some warning message')
+    end.to output(
+      "::warning::Some warning message\n"
+    ).to_stdout
+  end
+
+  it '#with_group writes the correct format' do
+    expect do
+      described_class.with_group('Some group name') do
+        puts 'Some message'
+      end
+    end.to output(
+      "::group::Some group name\n" \
+      "Some message\n" \
+      "::endgroup::\n"
+    ).to_stdout
+  end
+
+  it '#stop_commands writes the correct format' do
+    allow(SecureRandom).to receive(:hex).and_return('Some random value')
+
+    expect do
+      described_class.stop_commands do
+        puts 'Some message'
+      end
+    end.to output(
+      "::stop-commands::Some random value\n" \
+      "Some message\n" \
+      "::Some random value::\n"
+    ).to_stdout
+  end
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 0000000..cf1fd3a
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1,104 @@
+# frozen_string_literal: true
+
+# This file was generated by the `rspec --init` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+#
+# Given that it is always loaded, you are encouraged to keep this file as
+# light-weight as possible. Requiring heavyweight dependencies from this file
+# will add to the boot time of your test suite on EVERY test run, even for an
+# individual file that may not need all of that loaded. Instead, consider making
+# a separate helper file that requires the additional dependencies and performs
+# the additional setup, and require it from the spec files that actually need
+# it.
+#
+# See https://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+
+require_relative '../lib/gitlab_pipeline_action'
+
+Dir[File.expand_path('support/**/*.rb', __dir__)].each { |f| require f }
+
+RSpec.configure do |config|
+  # rspec-expectations config goes here. You can use an alternate
+  # assertion/expectation library such as wrong or the stdlib/minitest
+  # assertions if you prefer.
+  config.expect_with :rspec do |expectations|
+    # This option will default to `true` in RSpec 4. It makes the `description`
+    # and `failure_message` of custom matchers include text for helper methods
+    # defined using `chain`, e.g.:
+    #     be_bigger_than(2).and_smaller_than(4).description
+    #     # => "be bigger than 2 and smaller than 4"
+    # ...rather than:
+    #     # => "be bigger than 2"
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  # rspec-mocks config goes here. You can use an alternate test double
+  # library (such as bogus or mocha) by changing the `mock_with` option here.
+  config.mock_with :rspec do |mocks|
+    # Prevents you from mocking or stubbing a method that does not exist on
+    # a real object. This is generally recommended, and will default to
+    # `true` in RSpec 4.
+    mocks.verify_partial_doubles = true
+  end
+
+  # This option will default to `:apply_to_host_groups` in RSpec 4 (and will
+  # have no way to turn it off -- the option exists only for backwards
+  # compatibility in RSpec 3). It causes shared context metadata to be
+  # inherited by the metadata hash of host groups and examples, rather than
+  # triggering implicit auto-inclusion in groups with matching metadata.
+  config.shared_context_metadata_behavior = :apply_to_host_groups
+
+  # The action produces console output, using doc formatter to separate
+  # the output from different runs better
+  config.default_formatter = 'doc'
+
+  # The settings below are suggested to provide a good initial experience
+  # with RSpec, but feel free to customize to your heart's content.
+  #   # This allows you to limit a spec run to individual examples or groups
+  #   # you care about by tagging them with `:focus` metadata. When nothing
+  #   # is tagged with `:focus`, all examples get run. RSpec also provides
+  #   # aliases for `it`, `describe`, and `context` that include `:focus`
+  #   # metadata: `fit`, `fdescribe` and `fcontext`, respectively.
+  #   config.filter_run_when_matching :focus
+  #
+  #   # Allows RSpec to persist some state between runs in order to support
+  #   # the `--only-failures` and `--next-failure` CLI options. We recommend
+  #   # you configure your source control system to ignore this file.
+  #   config.example_status_persistence_file_path = "spec/examples.txt"
+  #
+  #   # Limits the available syntax to the non-monkey patched syntax that is
+  #   # recommended. For more details, see:
+  #   # https://rspec.info/features/3-12/rspec-core/configuration/zero-monkey-patching-mode/
+  #   config.disable_monkey_patching!
+  #
+  #   # This setting enables warnings. It's recommended, but in some cases may
+  #   # be too noisy due to issues in dependencies.
+  #   config.warnings = true
+  #
+  #   # Many RSpec users commonly either run the entire suite or an individual
+  #   # file, and it's useful to allow more verbose output when running an
+  #   # individual spec file.
+  #   if config.files_to_run.one?
+  #     # Use the documentation formatter for detailed output,
+  #     # unless a formatter has already been configured
+  #     # (e.g. via a command-line flag).
+  #     config.default_formatter = "doc"
+  #   end
+  #
+  #   # Print the 10 slowest examples and example groups at the
+  #   # end of the spec run, to help surface which specs are running
+  #   # particularly slow.
+  #   config.profile_examples = 10
+  #
+  #   # Run specs in random order to surface order dependencies. If you find an
+  #   # order dependency and want to debug it, you can fix the order by providing
+  #   # the seed, which is printed after each run.
+  #   #     --seed 1234
+  #   config.order = :random
+  #
+  #   # Seed global randomization in this process using the `--seed` CLI option.
+  #   # Setting this allows you to use `--seed` to deterministically reproduce
+  #   # test failures related to randomization by passing the same `--seed` value
+  #   # as the one that triggered the failure.
+  #   Kernel.srand config.seed
+end
diff --git a/spec/support/environment_variables.rb b/spec/support/environment_variables.rb
new file mode 100644
index 0000000..43705e5
--- /dev/null
+++ b/spec/support/environment_variables.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+RSpec.configure do
+  ENV['GITHUB_REPOSITORY'] = 'Taucher2003/GitLab-Pipeline-Action'
+  ENV['GITHUB_SHA'] = 'master'
+  ENV['GITHUB_REF'] = 'refs/heads/master'
+  ENV['GITHUB_REF_NAME'] = 'master'
+  ENV['GITHUB_SERVER_URL'] = 'https://github.com'
+
+  ENV['INPUT_GL_SERVER_URL'] = ENV.fetch('GITLAB_BASE_URL', 'http://127.0.0.1:8080')
+  ENV['INPUT_GL_SERVER_URL_FOR_RUNNER'] = ENV.fetch('GITLAB_BASE_URL_FOR_RUNNER', ENV.fetch('INPUT_GL_SERVER_URL', nil))
+  ENV['INPUT_GL_PROJECT_ID'] = ENV.fetch('GITLAB_PROJECT_ID', '1000')
+  ENV['INPUT_GL_RUNNER_TOKEN'] = ENV.fetch('GITLAB_RUNNER_TOKEN', 'some_long_runner_token')
+  ENV['INPUT_GL_API_TOKEN'] = ENV.fetch('GITLAB_TOKEN', 'TEST1234567890123456')
+end
diff --git a/spec/support/gitlab_instance.rb b/spec/support/gitlab_instance.rb
new file mode 100644
index 0000000..d2df02d
--- /dev/null
+++ b/spec/support/gitlab_instance.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+gitlab_not_running = false
+
+RSpec.configure do |config|
+  Gitlab.configure do |c|
+    c.endpoint = ENV.fetch('GITLAB_BASE_URL', 'http://127.0.0.1:8080/api/v4')
+    c.private_token = ENV.fetch('GITLAB_TOKEN', 'TEST1234567890123456')
+  end
+
+  begin
+    puts Gitlab.version.to_h
+  rescue Errno::ECONNREFUSED
+    gitlab_not_running = true
+  end
+
+  config.around(:each, :require_gitlab) do |example|
+    if gitlab_not_running
+      skip 'GitLab is not running'
+      next
+    end
+
+    example.run
+  end
+end
diff --git a/spec/support/negated_matchers.rb b/spec/support/negated_matchers.rb
new file mode 100644
index 0000000..2e29df0
--- /dev/null
+++ b/spec/support/negated_matchers.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+RSpec.configure do
+  RSpec::Matchers.define_negated_matcher :not_include, :include
+end
diff --git a/spec/support/stub_env.rb b/spec/support/stub_env.rb
new file mode 100644
index 0000000..26b9176
--- /dev/null
+++ b/spec/support/stub_env.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module StubEnv
+  def stub_env(key, value)
+    around do |example|
+      original_value = ENV.fetch(key, nil)
+      ENV[key] = value
+      example.run
+    ensure
+      ENV[key] = original_value
+    end
+  end
+end
+
+RSpec.configure do |config|
+  config.extend StubEnv
+end
diff --git a/spec/support/suppress_console_output.rb b/spec/support/suppress_console_output.rb
new file mode 100644
index 0000000..2bd236f
--- /dev/null
+++ b/spec/support/suppress_console_output.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+RSpec.configure do |config|
+  config.around(:each, :disable_console) do |example|
+    original_stdout = $stdout
+    original_stderr = $stderr
+
+    example_description = example.metadata[:full_description]
+    example_log_path = example_description.gsub(' ', '_').downcase
+
+    tmp_dir = File.expand_path("../../tmp/spec/logs/#{example_log_path}", __dir__)
+    FileUtils.mkdir_p tmp_dir
+
+    $stdout = File.open("#{tmp_dir}/stdout", 'w')
+    $stderr = File.open("#{tmp_dir}/stderr", 'w')
+
+    example.run
+
+    begin
+      $stdout.flush
+      $stderr.flush
+    ensure
+      $stdout.close
+      $stderr.close
+    end
+
+    $stdout = original_stdout
+    $stderr = original_stderr
+
+    if ENV['CI']
+      GitlabPipelineAction::Helper::Github.with_group "#{example_description} (stdout)" do
+        puts File.read "#{tmp_dir}/stdout"
+      end
+      GitlabPipelineAction::Helper::Github.with_group "#{example_description} (stderr)" do
+        puts File.read "#{tmp_dir}/stderr"
+      end
+    end
+  end
+end