diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..66f8ed3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/Gemfile.lock
diff --git a/Gemfile b/Gemfile
new file mode 100644
index 0000000..be173b2
--- /dev/null
+++ b/Gemfile
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+gemspec
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 0000000..8664943
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require 'minitest/test_task'
+
+Minitest::TestTask.create
+
+task default: :test
diff --git a/lib/ndjson.rb b/lib/ndjson.rb
index 6048885..56891e3 100644
--- a/lib/ndjson.rb
+++ b/lib/ndjson.rb
@@ -34,5 +34,8 @@ def write obj
       @output.puts JSON.generate(obj)
     end
 
+    def flush
+      @output.flush
+    end
   end
 end
diff --git a/ndjson.gemspec b/ndjson.gemspec
index 72f1278..0fa5a93 100644
--- a/ndjson.gemspec
+++ b/ndjson.gemspec
@@ -8,5 +8,8 @@ Gem::Specification.new do |s|
   s.email       = 'derfinn@gmail.com'
   s.files       = ['lib/ndjson.rb']
   s.homepage    = 'https://github.com/ndjson/ndjson.rb'
-  s.license       = 'MIT'
-end
\ No newline at end of file
+  s.license     = 'MIT'
+
+  s.add_development_dependency "minitest"
+  s.add_development_dependency "rake"
+end
diff --git a/test/example.ndjson b/test/example.ndjson
new file mode 100644
index 0000000..85fe14e
--- /dev/null
+++ b/test/example.ndjson
@@ -0,0 +1,3 @@
+ {"some":"thing"}
+ {"foo":17,"bar":false,"quux":true}
+ {"may":{"include":"nested","objects":["and","arrays"]}}
diff --git a/test/ndjson_test.rb b/test/ndjson_test.rb
new file mode 100644
index 0000000..67efe40
--- /dev/null
+++ b/test/ndjson_test.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require_relative 'test_helper'
+
+module NDJSONTest
+  class ParserTest < Minitest::Test
+    def test_initialize_with_path
+      parser = NDJSON::Parser.new(File.expand_path('example.ndjson', __dir__))
+      index = 0
+      parser.each do |entry|
+        assert_equal({ 'some' => 'thing' }, entry) if index.zero?
+        index += 1
+      end
+      assert_equal(index, 3)
+    end
+
+    def test_initialize_with_array
+      content = File.read(File.expand_path('example.ndjson', __dir__)).lines
+      parser = NDJSON::Parser.new(content)
+      index = 0
+      parser.each do |entry|
+        assert_equal({ 'some' => 'thing' }, entry) if index.zero?
+        index += 1
+      end
+      assert_equal(index, 3)
+    end
+  end
+
+  class GeneratorTest < Minitest::Test
+    def test_initialize_with_path
+      file = Tempfile.new('example.ndjson')
+      assert_equal(String, file.path.class)
+      path = file.path
+      generator = NDJSON::Generator.new(path)
+      generator.write({ 'some' => 'thing' })
+      generator.flush
+      assert_equal(%({"some":"thing"}\n), File.read(path))
+    end
+
+    def test_initialize_with_stringio
+      io = StringIO.new
+      generator = NDJSON::Generator.new(io)
+      generator.write({ 'some' => 'thing' })
+      io.rewind
+      assert_equal(%({"some":"thing"}\n), io.read)
+    end
+  end
+end
diff --git a/test/test_helper.rb b/test/test_helper.rb
new file mode 100644
index 0000000..a4c7480
--- /dev/null
+++ b/test/test_helper.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+$LOAD_PATH.unshift File.expand_path('../lib', __dir__)
+require 'ndjson'
+
+require 'tempfile'
+require 'stringio'
+require 'minitest/autorun'