checks-ocr\test(back): #5 add calculate iou unit test

- add `calculate_iou` unit test to `test_utils.py`
- add `unit-tests.yml` workflow

.github/workflows/unit-tests.yml

@@ -0,0 +1,25 @@
+name: Unit Tests
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python 3.11
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.11
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install pytest
+        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+    - name: Run tests with pytest
+      run: |
+        pytest test/unit/src

test/unit/src/test_utils.py

@@ -0,0 +1,16 @@
+from src.utils import calculate_iou
+
+import pytest
+
+@pytest.mark.parametrize(
+    ("box1", "box2", "expected"),
+    [
+        ((0.1, 0.1, 0.5, 0.5), (0.1, 0.1, 0.5, 0.5), 1.0,),
+        ((0.1, 0.1, 0.0, 0.0), (0.1, 0.1, 0.5, 0.5), 0.0,),
+        ((0.2, 0.2, 0.0, 0.0), (0.2, 0.2, 0.1, 0.0), 1/3,),
+    ],
+)
+def test_calculate_iou(box1: tuple, box2: tuple, expected: float) -> None:
+    iou = calculate_iou(box1, box2)
+    assert iou >= 0 and iou <= 1
+    assert pytest.approx(iou) == expected