refactor: split fit tests into granular focused tests

test_autoarray/fit/test_fit_dataset.py

@@ -3,7 +3,9 @@
 import autoarray as aa
 
 
-def test__figure_of_merit__with_inversion(masked_imaging_7x7, model_image_7x7):
+def test__figure_of_merit__with_inversion_and_regularization__equals_log_evidence(
+    masked_imaging_7x7, model_image_7x7
+):
     inversion = aa.m.MockInversion(
         linear_obj_list=[aa.m.MockMapper(regularization=aa.m.MockRegularization())],
         data_vector=1,
@@ -21,6 +23,10 @@ def test__figure_of_merit__with_inversion(masked_imaging_7x7, model_image_7x7):
 
     assert fit.figure_of_merit == fit.log_evidence
 
+
+def test__figure_of_merit__with_inversion_and_no_regularization__equals_log_likelihood(
+    masked_imaging_7x7, model_image_7x7
+):
     inversion = aa.m.MockInversion(
         linear_obj_list=[aa.m.MockLinearObj(regularization=None)], data_vector=1
     )
@@ -35,8 +41,8 @@ def test__figure_of_merit__with_inversion(masked_imaging_7x7, model_image_7x7):
     assert fit.figure_of_merit == fit.log_likelihood
 
 
-def test__figure_of_merit__with_noise_covariance_matrix_in_dataset(
-    masked_imaging_covariance_7x7, model_image_7x7, masked_imaging_7x7
+def test__chi_squared__with_noise_covariance_matrix__uses_covariance_weighted_formula(
+    masked_imaging_covariance_7x7, model_image_7x7
 ):
     fit = aa.m.MockFitImaging(
         dataset=masked_imaging_covariance_7x7,
@@ -51,21 +57,49 @@ def test__figure_of_merit__with_noise_covariance_matrix_in_dataset(
 
     assert fit.chi_squared == chi_squared
 
+
+def test__figure_of_merit__with_noise_covariance_matrix__equals_negative_half_chi_squared_plus_noise_normalization(
+    masked_imaging_covariance_7x7, model_image_7x7
+):
+    fit = aa.m.MockFitImaging(
+        dataset=masked_imaging_covariance_7x7,
+        use_mask_in_fit=False,
+        model_data=model_image_7x7,
+    )
+
     assert fit.figure_of_merit == pytest.approx(
         -0.5 * (fit.chi_squared + fit.noise_normalization), 1.0e-4
     )
 
-    fit = aa.m.MockFitImaging(
-        dataset=masked_imaging_7x7,
+
+def test__chi_squared__without_noise_covariance_matrix__differs_from_covariance_weighted_result(
+    masked_imaging_covariance_7x7, masked_imaging_7x7, model_image_7x7
+):
+    fit_with_covariance = aa.m.MockFitImaging(
+        dataset=masked_imaging_covariance_7x7,
         use_mask_in_fit=False,
         model_data=model_image_7x7,
     )
 
-    assert fit.chi_squared != pytest.approx(chi_squared, 1.0e-4)
+    chi_squared_covariance = aa.util.fit.chi_squared_with_noise_covariance_from(
+        residual_map=fit_with_covariance.residual_map,
+        noise_covariance_matrix_inv=masked_imaging_covariance_7x7.noise_covariance_matrix_inv,
+    )
 
+    fit_without_covariance = aa.m.MockFitImaging(
+        dataset=masked_imaging_7x7,
+        use_mask_in_fit=False,
+        model_data=model_image_7x7,
+    )
+
+    assert fit_without_covariance.chi_squared != pytest.approx(
+        chi_squared_covariance, 1.0e-4
+    )
 
-def test__grid_offset_via_data_model(imaging_7x7, mask_2d_7x7, model_image_7x7):
 
+def test__grids__with_dataset_model_grid_offset__lp_and_pixelization_grids_offset_correctly(
+    imaging_7x7, mask_2d_7x7, model_image_7x7
+):
     masked_imaging_7x7 = imaging_7x7.apply_mask(mask=mask_2d_7x7)
 
     fit = aa.m.MockFitImaging(
@@ -76,6 +110,5 @@ def test__grid_offset_via_data_model(imaging_7x7, mask_2d_7x7, model_image_7x7):
     )
 
     assert fit.dataset_model.grid_offset == (1.0, 2.0)
-
     assert fit.grids.lp[0] == pytest.approx((0.0, -3.0), 1.0e-4)
     assert fit.grids.pixelization[0] == pytest.approx((0.0, -3.0), 1.0e-4)

test_autoarray/fit/test_fit_imaging.py

@@ -3,102 +3,205 @@
 import autoarray as aa
 
 
-def test__data_and_model_are_identical__no_masking__check_values_are_correct():
-    mask = aa.Mask2D(mask=[[False, False], [False, False]], pixel_scales=(1.0, 1.0))
+# ---------------------------------------------------------------------------
+# Helper: build the "identical model, no masking" fit used by multiple tests
+# ---------------------------------------------------------------------------
 
+def _make_identical_fit_no_mask():
+    mask = aa.Mask2D(mask=[[False, False], [False, False]], pixel_scales=(1.0, 1.0))
     data = aa.Array2D(values=[1.0, 2.0, 3.0, 4.0], mask=mask)
     noise_map = aa.Array2D(values=[2.0, 2.0, 2.0, 2.0], mask=mask)
-
     dataset = aa.Imaging(data=data, noise_map=noise_map)
-
     dataset = dataset.apply_mask(mask=mask)
-
     model_data = aa.Array2D(values=[1.0, 2.0, 3.0, 4.0], mask=mask)
+    fit = aa.m.MockFitImaging(
+        dataset=dataset, use_mask_in_fit=False, model_data=model_data
+    )
+    return fit, noise_map
 
+
+def _make_different_fit_with_mask():
+    mask = aa.Mask2D(mask=[[False, False], [True, False]], pixel_scales=(1.0, 1.0))
+    data = aa.Array2D(values=[1.0, 2.0, 4.0], mask=mask)
+    noise_map = aa.Array2D(values=[2.0, 2.0, 2.0], mask=mask)
+    dataset = aa.Imaging(data=data, noise_map=noise_map)
+    model_data = aa.Array2D(values=[1.0, 2.0, 3.0], mask=mask)
     fit = aa.m.MockFitImaging(
         dataset=dataset, use_mask_in_fit=False, model_data=model_data
     )
+    return fit, noise_map
+
+
+def _make_identical_fit_with_inversion():
+    mask = aa.Mask2D(mask=[[False, False], [False, False]], pixel_scales=(1.0, 1.0))
+    data = aa.Array2D(values=[1.0, 2.0, 3.0, 4.0], mask=mask)
+    noise_map = aa.Array2D(values=[2.0, 2.0, 2.0, 2.0], mask=mask)
+    dataset = aa.Imaging(data=data, noise_map=noise_map)
+    dataset = dataset.apply_mask(mask=mask)
+    model_data = aa.Array2D(values=[1.0, 2.0, 3.0, 4.0], mask=mask)
+    inversion = aa.m.MockInversion(
+        linear_obj_list=[aa.m.MockMapper()],
+        data_vector=1,
+        regularization_term=2.0,
+        log_det_curvature_reg_matrix_term=3.0,
+        log_det_regularization_matrix_term=4.0,
+    )
+    fit = aa.m.MockFitImaging(
+        dataset=dataset,
+        use_mask_in_fit=False,
+        model_data=model_data,
+        inversion=inversion,
+    )
+    return fit, noise_map
+
+
+# ---------------------------------------------------------------------------
+# Tests: identical data and model, no masking
+# ---------------------------------------------------------------------------
+
+
+def test__mask__no_masking__returns_2x2_all_false_mask():
+    fit, _ = _make_identical_fit_no_mask()
 
     assert (fit.mask == np.array([[False, False], [False, False]])).all()
+
+
+def test__data__no_masking__returns_correct_data_values():
+    fit, _ = _make_identical_fit_no_mask()
+
     assert (fit.data == np.array([1.0, 2.0, 3.0, 4.0])).all()
+
+
+def test__noise_map__no_masking__returns_correct_noise_map_values():
+    fit, _ = _make_identical_fit_no_mask()
+
     assert (fit.noise_map == np.array([2.0, 2.0, 2.0, 2.0])).all()
+
+
+def test__signal_to_noise_map__no_masking__returns_correct_signal_to_noise_values():
+    fit, _ = _make_identical_fit_no_mask()
+
     assert (fit.signal_to_noise_map == np.array([0.5, 1.0, 1.5, 2.0])).all()
-    assert (fit.model_data == np.array([1.0, 2.0, 3.0, 4.0])).all()
+
+
+def test__residual_map__identical_data_and_model__all_zero_residuals():
+    fit, _ = _make_identical_fit_no_mask()
+
     assert (fit.residual_map == np.array([0.0, 0.0, 0.0, 0.0])).all()
+
+
+def test__normalized_residual_map__identical_data_and_model__all_zero_normalized_residuals():
+    fit, _ = _make_identical_fit_no_mask()
+
     assert (fit.normalized_residual_map == np.array([0.0, 0.0, 0.0, 0.0])).all()
+
+
+def test__chi_squared_map__identical_data_and_model__all_zero_chi_squared_map():
+    fit, _ = _make_identical_fit_no_mask()
+
     assert (fit.chi_squared_map == np.array([0.0, 0.0, 0.0, 0.0])).all()
 
+
+def test__chi_squared__identical_data_and_model__is_zero():
+    fit, _ = _make_identical_fit_no_mask()
+
     assert fit.chi_squared == 0.0
+
+
+def test__reduced_chi_squared__identical_data_and_model__is_zero():
+    fit, _ = _make_identical_fit_no_mask()
+
     assert fit.reduced_chi_squared == 0.0
+
+
+def test__noise_normalization__uniform_noise_map__correct_log_sum_formula():
+    fit, noise_map = _make_identical_fit_no_mask()
+
     assert fit.noise_normalization == np.sum(np.log(2 * np.pi * noise_map.array**2.0))
-    assert fit.log_likelihood == -0.5 * (fit.chi_squared + fit.noise_normalization)
 
 
-def test__data_and_model_are_different__include_masking__check_values_are_correct():
-    mask = aa.Mask2D(mask=[[False, False], [True, False]], pixel_scales=(1.0, 1.0))
+def test__log_likelihood__identical_data_and_model__negative_half_noise_normalization():
+    fit, _ = _make_identical_fit_no_mask()
 
-    data = aa.Array2D(values=[1.0, 2.0, 4.0], mask=mask)
-    noise_map = aa.Array2D(values=[2.0, 2.0, 2.0], mask=mask)
+    assert fit.log_likelihood == -0.5 * (fit.chi_squared + fit.noise_normalization)
 
-    dataset = aa.Imaging(data=data, noise_map=noise_map)
 
-    model_data = aa.Array2D(values=[1.0, 2.0, 3.0], mask=mask)
+# ---------------------------------------------------------------------------
+# Tests: different data and model with partial mask
+# ---------------------------------------------------------------------------
 
-    fit = aa.m.MockFitImaging(
-        dataset=dataset, use_mask_in_fit=False, model_data=model_data
-    )
 
-    assert (fit.mask == np.array([[False, False], [True, False]])).all()
-    assert (fit.data.slim == np.array([1.0, 2.0, 4.0])).all()
-    assert (fit.noise_map.slim == np.array([2.0, 2.0, 2.0])).all()
-    assert (fit.signal_to_noise_map.slim == np.array([0.5, 1.0, 2.0])).all()
-    assert (fit.model_data.slim == np.array([1.0, 2.0, 3.0])).all()
+def test__residual_map__different_data_and_model_with_partial_mask__correct_slim_residuals():
+    fit, _ = _make_different_fit_with_mask()
+
     assert (fit.residual_map.slim == np.array([0.0, 0.0, 1.0])).all()
+
+
+def test__normalized_residual_map__different_data_and_model_with_partial_mask__correct_slim_values():
+    fit, _ = _make_different_fit_with_mask()
+
     assert (fit.normalized_residual_map.slim == np.array([0.0, 0.0, 0.5])).all()
+
+
+def test__chi_squared_map__different_data_and_model_with_partial_mask__correct_slim_chi_squared():
+    fit, _ = _make_different_fit_with_mask()
+
     assert (fit.chi_squared_map.slim == np.array([0.0, 0.0, 0.25])).all()
 
+
+def test__chi_squared__different_model_with_masked_data__correct_value():
+    fit, _ = _make_different_fit_with_mask()
+
     assert fit.chi_squared == 0.25
+
+
+def test__reduced_chi_squared__different_model_with_masked_data__divided_by_unmasked_pixel_count():
+    fit, _ = _make_different_fit_with_mask()
+
     assert fit.reduced_chi_squared == 0.25 / 3.0
+
+
+def test__log_likelihood__different_model_with_masked_data__correct_value():
+    fit, noise_map = _make_different_fit_with_mask()
+
     assert fit.noise_normalization == np.sum(np.log(2 * np.pi * noise_map.array**2.0))
     assert fit.log_likelihood == -0.5 * (fit.chi_squared + fit.noise_normalization)
 
 
-def test__data_and_model_are_identical__inversion_included__changes_certain_properties():
-    mask = aa.Mask2D(mask=[[False, False], [False, False]], pixel_scales=(1.0, 1.0))
+# ---------------------------------------------------------------------------
+# Tests: identical data and model with inversion
+# ---------------------------------------------------------------------------
 
-    data = aa.Array2D(values=[1.0, 2.0, 3.0, 4.0], mask=mask)
-    noise_map = aa.Array2D(values=[2.0, 2.0, 2.0, 2.0], mask=mask)
 
-    dataset = aa.Imaging(data=data, noise_map=noise_map)
+def test__chi_squared__identical_data_and_model_with_inversion__is_zero():
+    fit, _ = _make_identical_fit_with_inversion()
 
-    dataset = dataset.apply_mask(mask=mask)
+    assert fit.chi_squared == 0.0
 
-    model_data = aa.Array2D(values=[1.0, 2.0, 3.0, 4.0], mask=mask)
 
-    inversion = aa.m.MockInversion(
-        linear_obj_list=[aa.m.MockMapper()],
-        data_vector=1,
-        regularization_term=2.0,
-        log_det_curvature_reg_matrix_term=3.0,
-        log_det_regularization_matrix_term=4.0,
-    )
-
-    fit = aa.m.MockFitImaging(
-        dataset=dataset,
-        use_mask_in_fit=False,
-        model_data=model_data,
-        inversion=inversion,
-    )
+def test__reduced_chi_squared__identical_data_and_model_with_inversion__is_zero():
+    fit, _ = _make_identical_fit_with_inversion()
 
-    assert fit.chi_squared == 0.0
     assert fit.reduced_chi_squared == 0.0
-    assert fit.noise_normalization == np.sum(np.log(2 * np.pi * noise_map.array**2.0))
-    assert fit.log_likelihood == -0.5 * (fit.chi_squared + fit.noise_normalization)
+
+
+def test__log_likelihood_with_regularization__with_inversion__adds_regularization_term():
+    fit, noise_map = _make_identical_fit_with_inversion()
 
     assert fit.log_likelihood_with_regularization == -0.5 * (
         fit.chi_squared + 2.0 + fit.noise_normalization
     )
+
+
+def test__log_evidence__with_inversion__uses_chi_squared_reg_and_determinant_terms():
+    fit, noise_map = _make_identical_fit_with_inversion()
+
     assert fit.log_evidence == -0.5 * (
         fit.chi_squared + 2.0 + 3.0 - 4.0 + fit.noise_normalization
     )
+
+
+def test__figure_of_merit__with_inversion__equals_log_evidence():
+    fit, _ = _make_identical_fit_with_inversion()
+
     assert fit.figure_of_merit == fit.log_evidence