Add test for duplicate uploads of a Puppet module

Add a new test case, `DuplicateUploadsTestCase`, in module
`pulp_smash.tests.puppet.api_v2.test_duplicate_uploads`. This module
uploads and imports a Puppet module into a single repository twice in a
row, and verifies that the procedure completes without any issues. The
new test case passes. Tests executed with:

    python -m unittest2 \
        pulp_smash.tests.puppet.api_v2.test_duplicate_uploads

Related to #81.

pulp_smash/tests/puppet/api_v2/test_duplicate_uploads.py

@@ -0,0 +1,78 @@
+# coding=utf-8
+"""Tests for how well Pulp can deal with duplicate uploads.
+
+This module targets `Pulp #1406`_ and `Pulp Smash #81`_. The test procedure is
+as follows:
+
+1. Create a new feed-less repository.
+2. Upload content and import it into the repository. Assert the upload and
+   import was successful.
+3. Upload identical content and import it into the repository.
+
+The second upload should silently fail for all Pulp releases in the 2.x series.
+
+.. _Pulp #1406: https://pulp.plan.io/issues/1406
+.. _Pulp Smash #81: https://github.com/PulpQE/pulp-smash/issues/81
+"""
+from __future__ import unicode_literals
+
+from pulp_smash import api, utils
+from pulp_smash.compat import urljoin
+from pulp_smash.constants import (
+    CONTENT_UPLOAD_PATH,
+    PUPPET_MODULE_URL,
+    REPOSITORY_PATH,
+)
+from pulp_smash.tests.puppet.api_v2.utils import gen_repo
+
+
+def _upload_import_puppet_module(server_config, puppet_module, repo_href):
+    """Upload a puppet module and import it into a repository.
+
+    Return the JSON-decoded body of the call report received when importing the
+    Puppet module.
+    """
+    client = api.Client(server_config, api.json_handler)
+    malloc = client.post(CONTENT_UPLOAD_PATH)
+    client.put(urljoin(malloc['_href'], '0/'), data=puppet_module)
+    call_report = client.post(urljoin(repo_href, 'actions/import_upload/'), {
+        'unit_key': {},
+        'unit_type_id': 'puppet_module',
+        'upload_id': malloc['upload_id'],
+    })
+    client.delete(malloc['_href'])
+    return call_report
+
+
+class DuplicateUploadsTestCase(utils.BaseAPITestCase):
+    """Test how well Pulp can deal with duplicate uploads."""
+
+    @classmethod
+    def setUpClass(cls):
+        """Create a Puppet repository. Upload a Puppet module into it twice."""
+        super(DuplicateUploadsTestCase, cls).setUpClass()
+
+        # Download content.
+        client = api.Client(cls.cfg)
+        puppet_module = client.get(PUPPET_MODULE_URL).content
+
+        # Create a feed-less repository.
+        client.response_handler = api.json_handler
+        repo = client.post(REPOSITORY_PATH, gen_repo())
+        cls.resources.add(repo['_href'])
+
+        # Upload and import the puppet module into the repository, twice.
+        cls.call_reports = tuple((
+            _upload_import_puppet_module(cls.cfg, puppet_module, repo['_href'])
+            for _ in range(2)
+        ))
+
+    def test_call_report_result(self):
+        """Assert each call report's "result" field is null.
+
+        Other checks are done automatically by
+        :func:`pulp_smash.api.json_handler`. See it for details.
+        """
+        for i, call_report in enumerate(self.call_reports):
+            with self.subTest(i=i):
+                self.assertIsNone(call_report['result'])