diff --git a/spec/index_writer/add_spec.rb b/spec/index_writer/add_spec.rb
new file mode 100644
index 0000000..5179b6b
--- /dev/null
+++ b/spec/index_writer/add_spec.rb
@@ -0,0 +1,23 @@
+require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
+
+describe "IndexWriter#add" do
+  before :all do
+    @doc1 = Spec::FooDocument.new :id => 1
+    @doc2 = Spec::FooDocument.new :id => 2
+  end
+
+  before do
+    @path = prepare_index_dir
+  end
+
+  it "adds the object to the list of objects" do
+    w = Polecat::IndexWriter.new @path
+    w.add @doc1
+    w.count.should == 1
+  end
+
+  it "raises an error, when the object is not a document" do
+    lambda { Polecat::IndexWriter.new(@path).add "foo" }.should(
+      raise_error(ArgumentError))
+  end
+end
diff --git a/spec/index_writer/count_spec.rb b/spec/index_writer/count_spec.rb
new file mode 100644
index 0000000..6f58b20
--- /dev/null
+++ b/spec/index_writer/count_spec.rb
@@ -0,0 +1,18 @@
+require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
+
+describe "IndexWriter#count" do
+  before :all do
+    @path = prepare_index_dir
+  end
+
+  it "returns 0 on an empty writer" do
+    w = Polecat::IndexWriter.new @path
+    w.count.should == 0
+  end
+
+  it "returns the number of documents stored in the storage" do
+    w = Polecat::IndexWriter.new @path
+    w.add Spec::FooDocument.new
+    w.count.should == 1
+  end
+end
diff --git a/spec/index_writer/new_spec.rb b/spec/index_writer/new_spec.rb
new file mode 100644
index 0000000..0458b64
--- /dev/null
+++ b/spec/index_writer/new_spec.rb
@@ -0,0 +1,27 @@
+require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
+
+describe "IndexWriter#new" do
+  before :all do
+    @path = prepare_index_dir
+  end
+
+  it "takes a path as an argument" do
+    writer = Polecat::IndexWriter.new @path
+    writer.path.should == @path
+  end
+
+  it "raises an Argument when no path is given" do
+    lambda { Polecat::IndexWriter.new }.should raise_error(ArgumentError)
+  end
+
+  it "raises an error, when the path is not directory" do
+    lambda {
+      Polecat::IndexWriter.new "/dev/null" 
+    }.should raise_error(ArgumentError)
+  end
+
+  it "raises an error when a index.lock file is in the directory" do
+    FileUtils.touch @path + '/index.lock'
+    lambda { Polecat::IndexWriter.new @path }.should raise_error(IOError)
+  end
+end
diff --git a/spec/index_writer/write_spec.rb b/spec/index_writer/write_spec.rb
new file mode 100644
index 0000000..dbf151f
--- /dev/null
+++ b/spec/index_writer/write_spec.rb
@@ -0,0 +1,42 @@
+require File.expand_path(File.dirname(__FILE__) + '/../spec_helper')
+
+describe "IndexWriter#write" do
+  before do
+    @path = prepare_index_dir
+  end
+
+  it "sets count to 0" do
+    w = Polecat::IndexWriter.new @path
+    w.add Spec::FooDocument.new
+    w.write
+    w.count.should == 0
+  end
+
+  it "returns true when the write was a success" do
+    w = Polecat::IndexWriter.new @path
+    w.add Spec::FooDocument.new
+    w.write.should == true
+  end
+
+  it "removes the lock after a write" do
+    w = Polecat::IndexWriter.new @path
+    w.add Spec::FooDocument.new
+    w.write
+    File.exists?(@path + '/index.lock').should == false
+  end
+
+  it "writes a marshalled representation of the document list" do
+    w = Polecat::IndexWriter.new @path
+    doc = Spec::FooDocument.new
+    w.add doc
+    w.write
+    File.read(@path + '/ind0.ind').should == Marshal.dump([doc])
+  end
+
+  it "returns false when the directory has an 'index.lock' file" do
+    w = Polecat::IndexWriter.new @path
+    FileUtils.touch @path + '/index.lock'
+    w.add Spec::FooDocument.new
+    w.write.should == false
+  end
+end