Add standalone sample input for simple_imager, integrate into unit-test.

This makes it possible to test imaging routines without first generating
the test-data with CASA.

Author: timstaley

src/fastimgproto/resources/__init__.py

@@ -0,0 +1,6 @@
+import os
+
+testdata_dir = __path__[0]
+
+simple_vis_npz_filepath = os.path.join(testdata_dir,
+                                       'simple_vis.npz')

src/fastimgproto/resources/testdata/__init__.py

@@ -0,0 +1,32 @@
+import json
+import numpy as np
+
+from click.testing import CliRunner
+from fastimgproto.resources.testdata import simple_vis_npz_filepath
+from fastimgproto.scripts.simple_imager import ConfigKeys, \
+    cli as simple_imager_cli
+
+
+def test_simple_imager():
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        config_filename = 'imager_conf.json'
+        output_filename = 'image.npz'
+        conf = {
+            ConfigKeys.image_size_pix: 1024,
+            ConfigKeys.cell_size_arcsec: 3.
+        }
+        with open(config_filename, 'w') as f:
+            json.dump(conf, f)
+
+        result = runner.invoke(simple_imager_cli,
+                               [
+                                   config_filename,
+                                   simple_vis_npz_filepath,
+                                   output_filename
+                               ])
+        assert result.exit_code == 0
+        with open(output_filename, 'rb') as f:
+            output_data = np.load(f)
+            assert 'image' in output_data
+            assert 'beam' in output_data