Merge pull request #88 from Johannes-Sahlmann/test-preview_image

Test preview image

docs/source/tests.rst

@@ -10,3 +10,6 @@ tests
 
 .. automodule:: jwql.tests.test_utils
     :members:
+
+.. automodule:: jwql.tests.test_preview_image
+    :members:

jwql/tests/test_preview_image.py

@@ -0,0 +1,105 @@
+#! /usr/bin/env python
+
+"""Tests for the ``preview_image`` module.
+
+Authors
+-------
+
+    - Johannes Sahlmann
+
+
+Use
+---
+
+    These tests can be run via the command line (omit the ``-s`` to
+    suppress verbose output to ``stdout``):
+
+    ::
+
+        pytest -s test_preview_image.py
+"""
+
+import glob
+import os
+import pytest
+
+from astropy.io import fits
+
+from jwql.preview_image.preview_image import PreviewImage
+
+# directory to be created and populated during tests running
+TEST_DIRECTORY = os.path.join(os.environ['HOME'], 'preview_image_test')
+
+# directory that contains sample images
+TEST_DATA_DIRECTORY = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'test_data')
+
+@pytest.fixture(scope="module")
+def test_directory(test_dir=TEST_DIRECTORY):
+    """Create a test directory for preview image.
+
+    Parameters
+    ----------
+    test_dir : str
+        Path to directory used for testing
+
+    Yields
+    -------
+    test_dir : str
+        Path to directory used for testing
+
+    """
+    os.mkdir(test_dir)  # creates directory
+    yield test_dir
+    print("teardown test directory")
+    if os.path.isdir(test_dir):
+        os.rmdir(test_dir)
+
+
+def test_make_image(test_directory):
+    """Use PreviewImage.make_image to create preview images of a sample JWST exposure.
+
+    Assert that the number of JPGs created corresponds to the number of integrations.
+
+    Parameters
+    ----------
+    test_directory : str
+        Path of directory used for testing
+
+    """
+    filenames = glob.glob(os.path.join(TEST_DATA_DIRECTORY, '*.fits'))
+    print('\nGenerating preview images for {}.'.format(filenames))
+
+    output_directory = test_directory
+
+    for filename in filenames:
+
+        header = fits.getheader(filename)
+
+        # Create and save the preview image or thumbnail
+        for create_thumbnail in [False, True]:
+            try:
+                image = PreviewImage(filename, "SCI")
+                image.clip_percent = 0.01
+                image.scaling = 'log'
+                image.cmap = 'viridis'
+                image.output_format = 'jpg'
+                image.thumbnail = create_thumbnail
+                image.output_directory = output_directory
+                image.make_image()
+            except ValueError as error:
+                print(error)
+
+            if create_thumbnail:
+                extension = 'thumb'
+            else:
+                extension = 'jpg'
+
+            # list of preview images
+            preview_image_filenames = glob.glob(os.path.join(test_directory, '*.{}'.format(
+                extension)))
+
+            assert len(preview_image_filenames) == header['NINTS']
+
+            # clean up: delete preview images
+            for file in preview_image_filenames:
+                os.remove(file)