Address problem with single job views (#211)

* Address problem with single job views

* Fix signature, add test

* Update changelog

changelog.txt

@@ -27,6 +27,7 @@ next
  - Fix issue causing a failure of the automatic conversion of valid key types (#168, #205).
  - Improve the 'dots in keys' error message to make it easier to fix related issues (#170, #205).
  - Update the ``__repr__`` and ``__repr_html__`` implementations of the ``Project`, ``Job``, and ``JobsCursor`` classes (#193).
+ - Fix issue with rendering views from the command line for single job project (#208).
  - Fix issue with heterogeneous types in state point values that are lists (#209).
 
 [1.1.0] -- 2019-05-19

signac/contrib/import_export.py

@@ -44,7 +44,9 @@ def _make_schema_based_path_function(jobs, exclude_keys=None, delimiter_nested='
     "Generate schema based paths as a function of the given jobs."
     from .schema import _build_job_statepoint_index
     if len(jobs) <= 1:
-        return lambda job: ''
+        # The lambda must (optionally) take a format spec argument to match the
+        # signature of the path function below.
+        return lambda job, sep=None: ''
 
     index = [{'_id': job._id, 'statepoint': job.sp()} for job in jobs]
     jsi = _build_job_statepoint_index(jobs=jobs, exclude_const=True, index=index)

tests/test_shell.py

@@ -142,6 +142,21 @@ def test_index(self):
         self.assertIn('b', doc)
         self.assertEqual(doc['b'], 0)
 
+    def test_view_single(self):
+        """Check whether command line views work for single job workspaces."""
+        self.call('python -m signac init my_project'.split())
+        project = signac.Project()
+        sps = [{'a': i} for i in range(1)]
+        for sp in sps:
+            project.open_job(sp).init()
+        os.mkdir('view')
+        self.call('python -m signac view'.split())
+        for sp in sps:
+            self.assertTrue(os.path.isdir('view/job'))
+            self.assertEqual(
+                os.path.realpath('view/job'),
+                os.path.realpath(project.open_job(sp).workspace()))
+
     def test_view(self):
         self.call('python -m signac init my_project'.split())
         project = signac.Project()