Add --tail flag as option on logs.

Closes #265
Signed-off-by: Stéphane Seguin <stephseguin93@gmail.com>

tests/acceptance/cli_test.py

@@ -1171,6 +1171,14 @@ class CLITestCase(DockerClientTestCase):
 
         self.assertRegexpMatches(result.stdout, '(\d{4})-(\d{2})-(\d{2})T(\d{2})\:(\d{2})\:(\d{2})')
 
+    def test_logs_tail(self):
+        self.base_dir = 'tests/fixtures/logs-tail-composefile'
+        self.dispatch(['up'], None)
+
+        result = self.dispatch(['logs', '--tail', '2'], None)
+
+        assert result.stdout.count('\n') == 3
+
     def test_kill(self):
         self.dispatch(['up', '-d'], None)
         service = self.project.get_service('simple')

tests/fixtures/logs-tail-composefile/docker-compose.yml

@@ -0,0 +1,3 @@
+simple:
+  image: busybox:latest
+  command: sh -c "echo a && echo b && echo c && echo d"

tests/unit/cli/log_printer_test.py

@@ -47,7 +47,7 @@ class TestLogPrinter(object):
         # Call count is 2 lines + "container exited line"
         assert output_stream.flush.call_count == 3
 
-    def test_single_container_without_follow(self, output_stream, mock_container):
+    def test_single_container_without_stream(self, output_stream, mock_container):
         LogPrinter([mock_container], output=output_stream, follow=False).run()
 
         output = output_stream.getvalue()