diff -r cba9fb39bcdb -r a38e6916504c spec/ezmlm/list/thread_spec.rb
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/ezmlm/list/thread_spec.rb	Fri May 12 11:09:36 2017 -0700
@@ -0,0 +1,87 @@
+# vim: set nosta noet ts=4 sw=4 ft=rspec:
+
+require_relative '../../spec_helpers'
+
+
+describe Ezmlm::List::Thread do
+
+	before( :all ) do
+		@listdir = make_listdir()
+	end
+
+	after( :all ) do
+		rm_r( @listdir )
+	end
+
+	let( :list ) do
+		Ezmlm::List.new( @listdir )
+	end
+
+	let ( :thread_id ) { "hdohjgmgfakappbhjnkp" }
+
+
+	context 'instantiating' do
+
+		it 'raises error if provided an unknown list object' do
+			expect {
+				described_class.new( true, 1 )
+			}.to raise_error( ArgumentError, /unknown list/i )
+		end
+
+		it 'raises error if thread indexing is disabled' do
+			expect( list ).to receive( :threaded? ).and_return( false )
+			expect {
+				described_class.new( list, thread_id )
+			}.to raise_error( RuntimeError, /indexing is not enabled/i )
+		end
+
+		it 'raises error if passed a malformed thread ID' do
+			expect {
+				described_class.new( list, 'whatever' )
+			}.to raise_error( ArgumentError, /malformed/i )
+		end
+
+		it 'raises error when unable to read thread file' do
+			allow( list ).to receive( :listdir ).and_return( Pathname('/nope') )
+			expect( list ).to receive( :threaded? ).and_return( true )
+			expect {
+				described_class.new( list, thread_id )
+			}.to raise_error( RuntimeError, /unknown thread/i )
+		end
+
+		it 'parses a thread index from the archive' do
+			thread = described_class.new( list, thread_id  )
+			expect( thread ).to be_a( Ezmlm::List::Thread )
+		end
+
+
+		context 'an instance of' do
+
+			let( :thread ) { described_class.new( list, thread_id ) }
+
+			it 'knows its subject' do
+				expect( thread.subject ).to match( /ai on the microchip/i )
+			end
+
+			it 'contains a list of message ids' do
+				expect( thread.messages ).to eq( [20, 108] )
+			end
+
+			it 'contains a list of author ids' do
+				expect( thread.authors ).to eq( ["mdncdmmkeffdjkopffbj", "ffcambaeljjifcodfjoc"] )
+			end
+
+			it 'holds messages that belong to the thread' do
+				expect( thread.messages.size ).to be( 2 )
+				expect( thread.first.subject ).to match( /microchip/i )
+				expect( thread.first.body.to_s ).to match( /protocol/i )
+				expect( thread.first.from.first ).to match( /block@example.net/i )
+			end
+
+			it 'is enumerable' do
+				expect( thread.any?{|m| m.id == 20 }).to be_truthy
+			end
+		end
+	end
+end
+