Add tests and documentation for management commands

Author: codingjoe

docs/commands.rst

@@ -7,4 +7,38 @@ Management Commands
 render_process_graph
 --------------------
 
-Render graphs for all processes as SVG files to the working directory.
+Render process graph to file::
+
+    usage: manage.py render_process_graph [-h] [-f {svg,pdf,png}] [-d DIRECTORY]
+                                          [-c] [--version] [-v {0,1,2,3}]
+                                          [--settings SETTINGS]
+                                          [--pythonpath PYTHONPATH] [--traceback]
+                                          [--no-color]
+                                          [model [model ...]]
+
+    Render process graph to file.
+
+    positional arguments:
+      model
+
+    optional arguments:
+      -h, --help            show this help message and exit
+      -f {svg,pdf,png}, --format {svg,pdf,png}
+                            Output file format. Default: svg
+      -d DIRECTORY, --directory DIRECTORY
+                            Output directory. Default is current working
+                            directory.
+      -c, --cleanup         Remove dot-files after rendering.
+      --version             show program's version number and exit
+      -v {0,1,2,3}, --verbosity {0,1,2,3}
+                            Verbosity level; 0=minimal output, 1=normal output,
+                            2=verbose output, 3=very verbose output
+      --settings SETTINGS   The Python path to a settings module, e.g.
+                            "myproject.settings.main". If this isn't provided, the
+                            DJANGO_SETTINGS_MODULE environment variable will be
+                            used.
+      --pythonpath PYTHONPATH
+                            A directory to add to the Python path, e.g.
+                            "/home/djangoprojects/myproject".
+      --traceback           Raise on CommandError exceptions
+      --no-color            Don't colorize the command output.

galahad/management/commands/render_process_graph.py

@@ -1,13 +1,19 @@
 from django.apps import apps
 from django.core.management import BaseCommand
 
+from galahad import utils
 from galahad.models import Process
 
 
 class Command(BaseCommand):
-    help = "Render graphs for all processes as SVG files to the working directory"
+    help = "Render process graph to file."
 
     def add_arguments(self, parser):
+        parser.add_argument(
+            'model',
+            nargs='*',
+            type=str,
+        )
         parser.add_argument(
             '-f', '--format',
             dest='format', type=str,
@@ -28,12 +34,18 @@ def add_arguments(self, parser):
         )
 
     def handle(self, *args, **options):
+        models = options['model']
         verbosity = options['verbosity']
         file_format = options['format']
         cleanup = options['cleanup']
         directory = options.get('directory', None)
 
-        for model in apps.get_models():
+        models = [
+            apps.get_model(s)
+            for s in models
+        ] or utils.get_processes()
+
+        for model in models:
             if issubclass(model, Process) and model != Process:
                 opt = model._meta
                 if verbosity > 0:
@@ -47,3 +59,5 @@ def handle(self, *args, **options):
                 graph.render(filename=filename, directory=directory, cleanup=cleanup)
                 if verbosity > 0:
                     self.stdout.write("Done!", self.style.SUCCESS)
+            else:
+                self.stderr.write("%r is not a Process subclass" % model, self.style.WARNING)

tests/commands/__init__.py

@@ -0,0 +1,47 @@
+import os
+import tempfile
+from pathlib import Path
+
+from django.core.management import call_command
+
+
+def test_call_no_args():
+    tmp_dir = Path(tempfile.mkdtemp())
+    call_command('render_process_graph', '-d', tmp_dir)
+    assert os.path.exists(str(tmp_dir / 'testapp_simpleprocess.svg'))
+    assert os.path.exists(str(tmp_dir / 'testapp_simpleprocess'))
+
+
+def test_call_cleanup():
+    tmp_dir = Path(tempfile.mkdtemp())
+    call_command('render_process_graph', '-d', tmp_dir, '-c')
+    assert os.path.exists(str(tmp_dir / 'testapp_simpleprocess.svg'))
+    assert not os.path.exists(str(tmp_dir / 'testapp_simpleprocess'))
+
+
+def test_call_format_pdf():
+    tmp_dir = Path(tempfile.mkdtemp())
+    call_command('render_process_graph', '-d', tmp_dir, '-f', 'pdf')
+    assert os.path.exists(str(tmp_dir / 'testapp_simpleprocess.pdf'))
+
+
+def test_call_format_png():
+    tmp_dir = Path(tempfile.mkdtemp())
+    call_command('render_process_graph', '-d', tmp_dir, '-f', 'png')
+    assert os.path.exists(str(tmp_dir / 'testapp_simpleprocess.png'))
+
+
+def test_call_explicit_processes():
+    tmp_dir = Path(tempfile.mkdtemp())
+    call_command('render_process_graph', '-d', tmp_dir, 'testapp.loopprocess', 'testapp.splitjoinprocess')
+    assert not os.path.exists(str(tmp_dir / 'testapp_simpleprocess.svg'))
+    assert os.path.exists(str(tmp_dir / 'testapp_loopprocess.svg'))
+    assert os.path.exists(str(tmp_dir / 'testapp_splitjoinprocess.svg'))
+
+
+def test_call_explicit_processes_invalid():
+    tmp_dir = Path(tempfile.mkdtemp())
+    call_command('render_process_graph', '-d', tmp_dir, 'auth.user', 'testapp.splitjoinprocess')
+    assert not os.path.exists(str(tmp_dir / 'testapp_simpleprocess.svg'))
+    assert not os.path.exists(str(tmp_dir / 'auth_user.svg'))
+    assert os.path.exists(str(tmp_dir / 'testapp_splitjoinprocess.svg'))