diff --git a/test/gems/gems/bad_example-100/lib/bad_example/basic.rb b/test/gems/gems/bad_example-100/lib/bad_example/basic.rb
new file mode 100644
index 0000000..9889425
--- /dev/null
+++ b/test/gems/gems/bad_example-100/lib/bad_example/basic.rb
@@ -0,0 +1,2 @@
+foo = nil
+true if @foo
diff --git a/test/gems/gems/bad_example-100/lib/bad_example/eval_redefined.rb b/test/gems/gems/bad_example-100/lib/bad_example/eval_redefined.rb
new file mode 100644
index 0000000..0390b3e
--- /dev/null
+++ b/test/gems/gems/bad_example-100/lib/bad_example/eval_redefined.rb
@@ -0,0 +1,2 @@
+eval "def foo; end"
+def foo; end
diff --git a/test/gems/specifications/bad_example-100.gemspec b/test/gems/specifications/bad_example-100.gemspec
new file mode 100644
index 0000000..43f0386
--- /dev/null
+++ b/test/gems/specifications/bad_example-100.gemspec
@@ -0,0 +1,19 @@
+# -*- encoding: utf-8 -*-
+# stub: bad_example 100 ruby lib
+
+Gem::Specification.new do |s|
+  s.name = "bad_example"
+  s.version = "100"
+
+  s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
+  s.require_paths = ["lib"]
+  s.authors = ["Semyon Perepelitsa"]
+  s.date = "2015-05-18"
+  s.email = "sema@sema.in"
+  s.homepage = "https://github.com/semaperepelitsa/ruby_warning_filter"
+  s.licenses = ["MIT"]
+  s.rubygems_version = "2.4.5"
+  s.summary = "***"
+
+  s.installed_by_version = "2.4.5" if s.respond_to? :installed_by_version
+end
diff --git a/test/integration_test.rb b/test/integration_test.rb
new file mode 100644
index 0000000..eceafdf
--- /dev/null
+++ b/test/integration_test.rb
@@ -0,0 +1,63 @@
+require "minitest/autorun"
+require "tempfile"
+
+class IntegrationTest < Minitest::Test
+  GEM_PATH = File.expand_path("#{__dir__}/gems")
+  GEM_PREFIX = File.join(GEM_PATH, "gems/bad_example-100/lib/bad_example")
+
+  LIB = File.expand_path("#{__dir__}/../lib")
+  CODE = <<-RUBY.gsub("\n", "; ")
+$VERBOSE = true
+require "ruby_warning_filter"
+$stderr = RubyWarningFilter.new($stderr)
+RUBY
+
+  def test_custom
+    assert_equal "Custom warning\n",
+      ruby(CODE, 'warn "Custom warning"')
+  end
+
+  def test_internal
+    assert_equal "-e:2: warning: instance variable @foo not initialized\n",
+      ruby(CODE, 'true if @foo')
+  end
+
+  def test_external_non_filtered
+    assert_equal <<-END, ruby('require "bad_example/basic"')
+#{GEM_PREFIX}/basic.rb:1: warning: assigned but unused variable - foo
+#{GEM_PREFIX}/basic.rb:2: warning: instance variable @foo not initialized
+END
+  end
+
+  def test_external
+    assert_equal "", ruby(CODE, 'require "bad_example/basic"')
+  end
+
+  def test_eval_redefined_non_filtered
+    assert_equal <<-END, ruby('require "bad_example/eval_redefined"')
+#{GEM_PREFIX}/eval_redefined.rb:2: warning: method redefined; discarding old foo
+(eval):1: warning: previous definition of foo was here
+END
+  end
+
+  def test_eval_redefined
+    assert_equal "", ruby(CODE, 'require "bad_example/eval_redefined"')
+  end
+
+  def test_with_backtrace
+    skip "Pending"
+  end
+
+  def ruby(*lines)
+    IO.pipe do |rd, wr|
+      success = system({ "GEM_PATH" => GEM_PATH }, "ruby", "-w", "-I", LIB, "-e", lines.join("\n"), :err => wr, unsetenv_others: true)
+      wr.close
+      out = rd.read
+      if success
+        out
+      else
+        raise out
+      end
+    end
+  end
+end