Ajoute l'analyse des pièces rares

tests/test_rare_parts_plot.py

@@ -0,0 +1,25 @@
+"""Tests du graphique des pièces rares par set."""
+
+import matplotlib
+from pathlib import Path
+
+from lib.plots.rare_parts import plot_rare_parts_per_set
+
+
+matplotlib.use("Agg")
+
+
+def test_plot_rare_parts_per_set_outputs_image(tmp_path: Path) -> None:
+    """Génère l'image du top des sets avec pièces exclusives."""
+    rare_by_set_path = tmp_path / "rare_parts_by_set.csv"
+    destination_path = tmp_path / "figures" / "step27" / "rare_parts_per_set.png"
+    rare_by_set_path.write_text(
+        "set_num,set_id,name,year,in_collection,rare_parts_distinct,rare_parts_quantity,rare_minifig_parts_distinct,rare_minifig_quantity\n"
+        "1000-1,1000,Set A,2020,true,3,5,1,2\n"
+        "2000-1,2000,Set B,2021,false,2,4,0,0\n"
+    )
+
+    plot_rare_parts_per_set(rare_by_set_path, destination_path)
+
+    assert destination_path.exists()
+    assert destination_path.stat().st_size > 0