feat: implement linting and testing

tests/test_helpers.py

@@ -0,0 +1,154 @@
+"""Tests for pure helper functions in data_platform.assets.funda."""
+
+from data_platform.assets.funda import (
+    _details_preview_table,
+    _safe,
+    _safe_int,
+    _search_preview_table,
+)
+
+# ── _safe_int ───────────────────────────────────────────────────────────────
+
+
+class TestSafeInt:
+    def test_none_returns_none(self):
+        assert _safe_int(None) is None
+
+    def test_integer_passthrough(self):
+        assert _safe_int(42) == 42
+
+    def test_negative_integer(self):
+        assert _safe_int(-10) == -10
+
+    def test_zero(self):
+        assert _safe_int(0) == 0
+
+    def test_string_int(self):
+        assert _safe_int("123") == 123
+
+    def test_float_truncated(self):
+        assert _safe_int(3.9) == 3
+
+    def test_float_string(self):
+        assert _safe_int("7.0") == 7
+
+    def test_non_numeric_string_returns_none(self):
+        assert _safe_int("abc") is None
+
+    def test_empty_string_returns_none(self):
+        assert _safe_int("") is None
+
+    def test_list_returns_none(self):
+        assert _safe_int([1, 2, 3]) is None
+
+
+# ── _safe ────────────────────────────────────────────────────────────────────
+
+
+class TestSafe:
+    def test_dict_becomes_json_string(self):
+        result = _safe({"key": "val"})
+        assert result == '{"key": "val"}'
+
+    def test_list_becomes_json_string(self):
+        result = _safe([1, 2, 3])
+        assert result == "[1, 2, 3]"
+
+    def test_tuple_becomes_json_string(self):
+        result = _safe((1, 2))
+        assert result == "[1, 2]"
+
+    def test_string_passthrough(self):
+        assert _safe("hello") == "hello"
+
+    def test_integer_passthrough(self):
+        assert _safe(99) == 99
+
+    def test_none_passthrough(self):
+        assert _safe(None) is None
+
+    def test_nested_dict_serialised(self):
+        data = {"a": {"b": [1, 2]}}
+        result = _safe(data)
+        import json
+
+        assert json.loads(result) == data
+
+
+# ── _search_preview_table ────────────────────────────────────────────────────
+
+
+class TestSearchPreviewTable:
+    def test_empty_rows_returns_header_only(self):
+        result = _search_preview_table([])
+        lines = result.split("\n")
+        assert len(lines) == 2
+        assert "Title" in lines[0]
+        assert "---" in lines[1]
+
+    def test_single_row_appears(self):
+        rows = [
+            {
+                "title": "Teststraat 1",
+                "city": "Amsterdam",
+                "price": 350000,
+                "living_area": 80,
+                "bedrooms": 3,
+            }
+        ]
+        result = _search_preview_table(rows)
+        assert "Teststraat 1" in result
+        assert "Amsterdam" in result
+        assert "€350,000" in result
+        assert "80 m²" in result
+        assert "3" in result
+
+    def test_missing_price_shows_dash(self):
+        rows = [{"title": "No Price", "city": "Rotterdam", "price": None}]
+        result = _search_preview_table(rows)
+        assert "–" in result
+
+    def test_missing_area_shows_dash(self):
+        rows = [{"title": "No Area", "city": "Utrecht", "living_area": None}]
+        result = _search_preview_table(rows)
+        assert "–" in result
+
+    def test_multiple_rows_correct_count(self):
+        rows = [{"title": f"St {i}", "city": "City", "price": i * 1000} for i in range(5)]
+        result = _search_preview_table(rows)
+        lines = result.split("\n")
+        # header + separator + 5 data rows
+        assert len(lines) == 7
+
+
+# ── _details_preview_table ───────────────────────────────────────────────────
+
+
+class TestDetailsPreviewTable:
+    def test_empty_rows_returns_header_only(self):
+        result = _details_preview_table([])
+        lines = result.split("\n")
+        assert len(lines) == 2
+        assert "Title" in lines[0]
+
+    def test_row_with_all_fields(self):
+        rows = [
+            {
+                "title": "Kerkstraat 5",
+                "city": "Haarlem",
+                "price": 425000,
+                "status": "available",
+                "energy_label": "A",
+            }
+        ]
+        result = _details_preview_table(rows)
+        assert "Kerkstraat 5" in result
+        assert "Haarlem" in result
+        assert "€425,000" in result
+        assert "available" in result
+        assert "A" in result
+
+    def test_missing_price_shows_dash(self):
+        rows = [{"title": "T", "city": "C", "price": None, "status": "sold"}]
+        result = _details_preview_table(rows)
+        assert "–" in result