Add parametrized unit test coverage

.github/workflows/pytest.yml

@@ -0,0 +1,19 @@
+name: Run pytest
+
+on: [pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install pytest
+
+      - name: Run pytest
+        run: pytest

.gitignore

@@ -1 +1,2 @@
 .idea
+.pytest_cache

scripts/sd_webui_aspect_ratio_helper.py

@@ -7,8 +7,9 @@ from modules import scripts
 from modules import shared
 from modules.shared import opts
 
-_MIN_DIMENSION = 64
-_MAX_DIMENSION = 2048
+from util import _scale_dimensions_to_max_dimension
+from util import _scale_by_percentage
+
 _EXTENSION_NAME = 'Aspect Ratio Helper'
 
 
@@ -56,35 +57,6 @@ def on_ui_settings():
     )
 
 
-def _scale_by_percentage(width, height, pct):
-    aspect_ratio = float(width) / float(height)
-    step = (pct - 1.0)
-    new_width = max(int(round(width * (1.0 + step))), 1)
-    new_height = max(int(round(new_width / aspect_ratio)), 1)
-    if new_width > _MAX_DIMENSION:
-        new_width = _MAX_DIMENSION
-        new_height = max(int(round(new_width / aspect_ratio)), 1)
-    if new_height > _MAX_DIMENSION:
-        new_height = _MAX_DIMENSION
-        new_width = max(int(round(new_height * aspect_ratio)), 1)
-    if new_width < _MIN_DIMENSION:
-        new_width = _MIN_DIMENSION
-        new_height = max(int(round(new_width / aspect_ratio)), 1)
-    if new_height < _MIN_DIMENSION:
-        new_height = _MIN_DIMENSION
-        new_width = max(int(round(new_height * aspect_ratio)), 1)
-    return new_width, new_height
-
-
-def _scale_dimensions_to_max_dimension(width, height, max_dim):
-    if max_dim == max(width, height):
-        return width, height
-    aspect_ratio = float(width) / float(height)
-    if width > height:
-        return max_dim, max(int(round(max_dim / aspect_ratio)), 1)
-    return max(int(round(max_dim * aspect_ratio)), 1), max_dim
-
-
 class AspectRatioStepScript(scripts.Script):
 
     def title(self):

scripts/util.py

@@ -0,0 +1,33 @@
+_MIN_DIMENSION = 64
+_MAX_DIMENSION = 2048
+
+
+def _scale_by_percentage(width, height, pct):
+    aspect_ratio = float(width) / float(height)
+    step = (pct - 1.0)
+    new_width = max(int(round(width * (1.0 + step))), 1)
+    new_height = max(int(round(new_width / aspect_ratio)), 1)
+    if new_width > _MAX_DIMENSION:
+        new_width = _MAX_DIMENSION
+        new_height = max(int(round(new_width / aspect_ratio)), 1)
+    if new_height > _MAX_DIMENSION:
+        new_height = _MAX_DIMENSION
+        new_width = max(int(round(new_height * aspect_ratio)), 1)
+    if new_width < _MIN_DIMENSION:
+        new_width = _MIN_DIMENSION
+        new_height = max(int(round(new_width / aspect_ratio)), 1)
+    if new_height < _MIN_DIMENSION:
+        new_height = _MIN_DIMENSION
+        new_width = max(int(round(new_height * aspect_ratio)), 1)
+    return new_width, new_height
+
+
+def _scale_dimensions_to_max_dimension(width, height, max_dim):
+    if not _MIN_DIMENSION < max_dim < _MAX_DIMENSION:
+        raise ValueError('Invalid dimension provided.')
+    if max_dim == max(width, height):
+        return width, height
+    aspect_ratio = float(width) / float(height)
+    if width > height:
+        return max_dim, max(int(round(max_dim / aspect_ratio)), 1)
+    return max(int(round(max_dim * aspect_ratio)), 1), max_dim

tests/util_test.py

@@ -0,0 +1,86 @@
+import pytest
+
+from scripts.util import _MIN_DIMENSION
+from scripts.util import _MAX_DIMENSION
+from scripts.util import _scale_by_percentage
+from scripts.util import _scale_dimensions_to_max_dimension
+
+
+@pytest.mark.parametrize(
+    "width, height, pct, expected",
+    [
+        pytest.param(200, 400, 0.5, (100, 200), id="50_percent_scale_down"),
+        pytest.param(100, 200, 2.0, (200, 400), id="200_percent_scale_up"),
+        pytest.param(100, 200, 1.1, (110, 220), id="10_percent_scale_up"),
+        pytest.param(100, 200, 0.9, (90, 180), id="10_percent_scale_down"),
+        pytest.param(100, 200, 0.0, (64, 128), id="scale_full_down"),
+        pytest.param(
+            _MIN_DIMENSION - 1,
+            _MIN_DIMENSION - 1,
+            0.5,
+            (_MIN_DIMENSION, _MIN_DIMENSION),
+            id="scale_below_min_dimension",
+        ),
+        pytest.param(
+            _MAX_DIMENSION + 1,
+            _MAX_DIMENSION + 1,
+            2.0,
+            (_MAX_DIMENSION, _MAX_DIMENSION),
+            id="scale_above_max_dimension",
+        ),
+    ],
+)
+def test_scale_by_percentage(
+        width, height, pct, expected
+):
+    assert _scale_by_percentage(
+        width, height, pct
+    ) == expected
+
+
+@pytest.mark.parametrize(
+    "width, height, max_dim, expected",
+    [
+        pytest.param(
+            100, 200, 400, (200, 400), id="scale_up_to_max_dimension_horizontally"
+        ),
+        pytest.param(
+            200, 100, 400, (400, 200), id="scale_up_to_max_dimension_vertically"
+        ),
+        pytest.param(
+            400, 64, 400, (400, 64), id="no_scale_up_needed_with_max_dimension_width"
+        ),
+        pytest.param(
+            64, 400, 400, (64, 400), id="no_scale_up_needed_with_max_dimension_height"
+        ),
+    ],
+)
+def test_scale_dimensions_to_max_dimension(
+        width, height, max_dim, expected
+):
+    assert _scale_dimensions_to_max_dimension(
+        width, height, max_dim
+    ) == expected
+
+
+@pytest.mark.parametrize(
+    "width, height, max_dim",
+    [
+        pytest.param(
+            64,
+            64,
+            _MIN_DIMENSION - 1,
+            id="scale_below_min_dimension",
+        ),
+        pytest.param(
+            64,
+            64,
+            _MAX_DIMENSION + 1,
+            id="scale_above_max_dimension",
+        ),
+
+    ],
+)
+def test_error_thrown_given_dim_outside_boundaries(width, height, max_dim):
+    with pytest.raises(ValueError):
+        _scale_dimensions_to_max_dimension(width, height, max_dim)