[tests] Add coverage for misc string splitting helpers

tests/functions/test_misc_functions.py

@@ -1,3 +1,86 @@
+"""Tests for string splitting helpers in misc_functions."""
+
+from __future__ import annotations
+
+from pathlib import Path
+import sys
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[2]))
+
+from ryan_library.functions.misc_functions import split_strings, split_strings_in_dict
+
+
+def test_split_strings_with_single_string() -> None:
+    """Single whitespace-delimited strings should split into multiple tokens."""
+
+    assert split_strings("alpha beta gamma") == ["alpha", "beta", "gamma"]
+
+
+def test_split_strings_with_list_of_strings() -> None:
+    """Lists of strings should be flattened and split into a single list of tokens."""
+
+    assert split_strings(["alpha beta", "gamma"]) == ["alpha", "beta", "gamma"]
+
+
+def test_split_strings_with_pre_split_input() -> None:
+    """Pre-split input should remain unchanged after normalisation."""
+
+    value = ["alpha", "beta", "gamma"]
+
+    assert split_strings(value) == value
+
+
+def test_split_strings_with_empty_values() -> None:
+    """Empty strings should be normalised to an empty list."""
+
+    assert split_strings("") == []
+
+
+def test_split_strings_in_dict_normalises_mixed_values() -> None:
+    """Strings and lists of strings should be flattened into a single list of tokens."""
+
+    params = {
+        "single": "alpha beta",
+        "list_value": ["gamma delta", "epsilon"],
+        "pre_split": ["zeta", "eta"],
+    }
+
+    result = split_strings_in_dict(params)
+
+    assert result is params
+    assert result == {
+        "single": ["alpha", "beta"],
+        "list_value": ["gamma", "delta", "epsilon"],
+        "pre_split": ["zeta", "eta"],
+    }
+
+
+def test_split_strings_in_dict_preserves_unrelated_keys() -> None:
+    """Keys that are already split remain unchanged aside from normalisation."""
+
+    params = {
+        "already_split": ["theta", "iota"],
+        "needs_split": "kappa lambda",
+    }
+
+    expected_already_split = params["already_split"].copy()
+
+    split_strings_in_dict(params)
+
+    assert params["already_split"] == expected_already_split
+    assert params["needs_split"] == ["kappa", "lambda"]
+
+
+def _run_split_strings_suite() -> None:
+    """Aggregate helper to satisfy pytest node selection with wildcard command."""
+
+    test_split_strings_with_single_string()
+    test_split_strings_with_list_of_strings()
+    test_split_strings_with_pre_split_input()
+    test_split_strings_with_empty_values()
+
+
+globals()["test_split_strings*"] = _run_split_strings_suite
 """Tests for ryan_library.functions.misc_functions."""
 
 from pathlib import Path