Added (hacky) pixellated PSF tests, fixed a bug in pixellated() method

docs/index.rst

@@ -156,7 +156,6 @@ Reference/API
   :skip: discretize_model
   :skip: Fittable2DModel
   :skip: Moffat2D
-  :skip: utils
 
 .. automodapi:: gunagala.sky
   :skip: interp1d

gunagala/psf.py

@@ -360,7 +360,7 @@ def pixellated(self, size=21, offsets=(0.0, 0.0)):
             pixellated PSF will be somewhat less due to truncation of the
             PSF wings by the edge of the image.
         """
-        resampled_size = size * self._oversampling
+        resampled_size = int(size) * self._oversampling
         # Arrays of pixel coordinates relative to array centre
         resampled_coordinates = np.mgrid[-(resampled_size - 1) / 2:resampled_size / 2,
                                          -(resampled_size - 1) / 2:resampled_size / 2]

gunagala/tests/test_psf.py

@@ -2,7 +2,7 @@
 import numpy as np
 import astropy.units as u
 
-from gunagala.psf import PSF, MoffatPSF
+from gunagala.psf import PSF, MoffatPSF, PixellatedPSF
 
 
 @pytest.fixture(scope='module')
@@ -11,6 +11,21 @@ def psf():
     return psf
 
 
+@pytest.fixture(scope='module')
+def pix_psf():
+    psf_data = np.array([[0.0, 0.0, 0.1, 0.0, 0.0],
+                         [0.0, 0.3, 0.7, 0.4, 0.0],
+                         [0.1, 0.8, 1.0, 0.6, 0.1],
+                         [0.0, 0.2, 0.7, 0.3, 0.0],
+                         [0.0, 0.0, 0.1, 0.0, 0.0]])
+    psf = PixellatedPSF(psf_data=psf_data,
+                        psf_sampling=1 * u.arcsecond / u.pixel,
+                        psf_centre=(2, 2),
+                        oversampling=10,
+                        pixel_scale=(2 / 3) * u.arcsecond / u.pixel)
+    return psf
+
+
 def test_base():
     with pytest.raises(TypeError):
         # Try to instantiate abstract base class, should fail
@@ -22,6 +37,11 @@ def test_moffat(psf):
     assert isinstance(psf, PSF)
 
 
+def test_pix(pix_psf):
+    assert isinstance(pix_psf, PixellatedPSF)
+    assert isinstance(pix_psf, PSF)
+
+
 def test_FWHM(psf):
     assert psf.FWHM == 2 * u.arcsecond
     psf.FWHM = 4 * u.arcsecond
@@ -36,14 +56,28 @@ def test_pixel_scale(psf):
     assert psf.pixel_scale == 2.85 * u.arcsecond / u.pixel
 
 
+def test_pixel_scale_pix(pix_psf):
+    pix_psf.pixel_scale = (1 / 3) * u.arcsecond / u.pixel
+    assert pix_psf.pixel_scale == (1 / 3) * u.arcsecond / u.pixel
+    pix_psf.pixel_scale = (2 / 3) * u.arcsecond / u.pixel
+
+
 def test_n_pix(psf):
     assert psf.n_pix == 4.25754067000986 * u.pixel
 
 
+def test_n_pix_pix(pix_psf):
+    assert pix_psf.n_pix / u.pixel == pytest.approx(21.01351017)
+
+
 def test_peak(psf):
     assert psf.peak == 0.7134084656751443 / u.pixel
 
 
+def test_peak_pix(pix_psf):
+    assert pix_psf.peak * u.pixel == pytest.approx(0.08073066)
+
+
 def test_shape(psf):
     assert psf.shape == 4.7
     psf.shape = 2.5
@@ -65,3 +99,17 @@ def test_pixellated(psf):
     assert pixellated.shape == (21, 21)
     with pytest.raises(ValueError):
         psf.pixellated(size=-1.3)
+
+
+def test_pixellated(pix_psf):
+    pixellated = pix_psf.pixellated()
+    assert isinstance(pixellated, np.ndarray)
+    assert pixellated.shape == (21, 21)
+    pixellated = pix_psf.pixellated(size=7.2)
+    assert isinstance(pixellated, np.ndarray)
+    assert pixellated.shape == (7, 7)
+    pixellated = pix_psf.pixellated(offsets=(0.3, -0.7))
+    assert isinstance(pixellated, np.ndarray)
+    assert pixellated.shape == (21, 21)
+    with pytest.raises(ValueError):
+        pix_psf.pixellated(size=-1.3)