refactor: dormancy calculations

src/ramstk/analyses/dormancy.py

@@ -4,11 +4,11 @@
 #       ramstk.analyses.Dormancy.py is part of the RAMSTK Project
 #
 # All rights reserved.
-# Copyright 2007 - 2024 Doyle Rowland doyle.rowland <AT> reliaqual <DOT> com
+# Copyright since 2007 Doyle Rowland doyle.rowland <AT> reliaqual <DOT> com
 """Dormancy Calculations Module."""
 
 # Standard Library Imports
-from typing import List, Union
+from typing import List, Optional, Union
 
 DORMANT_HR_MULTIPLIER = {
     "ground": {
@@ -50,20 +50,24 @@
 ]
 
 
-def get_environment_type(env_id: int, is_active: bool) -> str:
+def get_environment_type(env_id: int, is_active: bool) -> Optional[str]:
     """Get the environment type based on the environment ID.
 
     :param env_id: the index in the environment list.
     :param is_active: indicates whether or not to use the ENVIRONMENTS_ACTIVE list.
     :return: the name of the environment associated with the end_id.
     :rtype: str
     """
-    _index = env_id - 1
-    if is_active and _index < len(ENVIRONMENTS_ACTIVE):
-        return ENVIRONMENTS_ACTIVE[_index]
+    if env_id <= 0:
+        return None  # Invalid env_id, must be positive
 
-    if _index < len(ENVIRONMENTS_DORMANT):
+    _index = env_id - 1
+    if is_active:
+        if _index < len(ENVIRONMENTS_ACTIVE):
+            return ENVIRONMENTS_ACTIVE[_index]
+    elif _index < len(ENVIRONMENTS_DORMANT):
         return ENVIRONMENTS_DORMANT[_index]
+    return None
 
 
 def get_dormant_hr_multiplier(
@@ -165,11 +169,14 @@ def do_calculate_dormant_hazard_rate(
     :rtype: float
     :raise: IndexError if an indexing argument asks for a non-existent index.
     """
-    _env_active_id = get_environment_type(env_info[0], True)
-    _env_dormant_id = get_environment_type(env_info[1], False)
+    _env_active = get_environment_type(env_info[0], True)
+    _env_dormant = get_environment_type(env_info[1], False)
+
+    if _env_active is None or _env_dormant is None:
+        return 0.0
 
     _dormant_hr_multiplier = get_dormant_hr_multiplier(
-        hw_info, _env_active_id, _env_dormant_id
+        hw_info, _env_active, _env_dormant
     )
 
     return _dormant_hr_multiplier * hw_info[2]

tests/analyses/test_dormancy.py

@@ -66,6 +66,14 @@ def test_get_environment_type_dormant(dormant_env):
     )
 
 
+@pytest.mark.unit
+@pytest.mark.parametrize("env_id", [-1, 0, 14])
+def test_get_environment_type_invalid(env_id):
+    """get_environment_type() should return None for invalid environment IDs."""
+    assert get_environment_type(env_id, True) is None
+    assert get_environment_type(env_id, False) is None
+
+
 @pytest.mark.unit
 @pytest.mark.parametrize("category_id", [1, 2, 3, 4, 5, 6, 7, 8])
 def test_get_dormant_hr_multiplier_ground(category_id):
@@ -208,15 +216,21 @@ def test_get_dormant_hr_multiplier_space(category_id):
 def test_get_dormant_hr_multiplier_no_category():
     """get_dormant_hr_multiplier() should return 0.0 if the category ID is not in
     1-8."""
-    assert get_dormant_hr_multiplier([10, 1, 0.0], "ground", "ground") == 0.0
+    assert get_dormant_hr_multiplier([10, 1, 0.0], "ground", "ground") == pytest.approx(
+        0.0
+    )
 
 
 @pytest.mark.unit
 def test_get_dormant_hr_multiplier_no_environment():
     """get_dormant_hr_multiplier() should return 0.0 if the active/dormant environments
     combination is not valid."""
-    assert get_dormant_hr_multiplier([1, 1, 0.0], "missile", "ground") == 0.0
-    assert get_dormant_hr_multiplier([1, 1, 0.0], "ground", "airborne") == 0.0
+    assert get_dormant_hr_multiplier([1, 1, 0.0], "missile", "ground") == pytest.approx(
+        0.0
+    )
+    assert get_dormant_hr_multiplier(
+        [1, 1, 0.0], "ground", "airborne"
+    ) == pytest.approx(0.0)
 
 
 @pytest.mark.unit
@@ -241,12 +255,55 @@ def test_dormant_hazard_rate(category_id, subcategory_id, expected):
     assert _hr_dormant == pytest.approx(expected)
 
 
+@pytest.mark.unit
+def test_get_dormant_hr_multiplier_invalid_subcategory():
+    """get_dormant_hr_multiplier() should return 0.0 if the subcategory is out of range
+    for semiconductors."""
+    # Test with invalid subcategory for semiconductors.
+    assert get_dormant_hr_multiplier([2, 5, 0.0], "ground", "ground") == pytest.approx(
+        0.0
+    )
+
+
 @pytest.mark.unit
 @pytest.mark.calculation
 def test_dormant_hazard_rate_bad_index():
     """do_calculate_dormant_hazard_rate() should raise an IndexError when a bad index
     value is passed."""
-    # with pytest.raises(ValueError):
     _hr_dormant = do_calculate_dormant_hazard_rate(
         hw_info=[4, 5, 0.008642374], env_info=[3, 12]
     )
+
+
+@pytest.mark.unit
+def test_dormant_hazard_rate_invalid_environment():
+    """do_calculate_dormant_hazard_rate() should return 0.0 when an invalid environment
+    is passed."""
+    _hr_dormant = do_calculate_dormant_hazard_rate(
+        hw_info=[1, 1, 0.008642374], env_info=[14, 1]
+    )
+    assert _hr_dormant == pytest.approx(0.0)
+
+    _hr_dormant = do_calculate_dormant_hazard_rate(
+        hw_info=[1, 1, 0.008642374], env_info=[3, 5]
+    )
+    assert _hr_dormant == pytest.approx(0.0)
+
+
+@pytest.mark.unit
+def test_dormant_hazard_rate_zero_hazard_rate():
+    """do_calculate_dormant_hazard_rate() should return 0.0 when the hazard rate is
+    0."""
+    _hr_dormant = do_calculate_dormant_hazard_rate(hw_info=[1, 1, 0.0], env_info=[3, 1])
+    assert _hr_dormant == pytest.approx(0.0)
+
+
+@pytest.mark.unit
+@pytest.mark.parametrize("subcategory_id", [1, 2, 3, 4])
+def test_dormant_hazard_rate_category_1(subcategory_id):
+    """do_calculate_dormant_hazard_rate() should handle different subcategories of
+    category 1."""
+    _hr_dormant = do_calculate_dormant_hazard_rate(
+        hw_info=[1, subcategory_id, 0.008642374], env_info=[3, 1]
+    )
+    assert isinstance(_hr_dormant, float)