Ajoute le graphique du nombre de minifigs par set

tests/test_minifig_counts_plot.py

@@ -0,0 +1,25 @@
+"""Tests du graphique des minifigs par set."""
+
+import matplotlib
+from pathlib import Path
+
+from lib.plots.minifig_counts import plot_minifigs_per_set
+
+
+matplotlib.use("Agg")
+
+
+def test_plot_minifigs_per_set_outputs_image(tmp_path: Path) -> None:
+    """Génère l'image du nombre de minifigs par set."""
+    counts_path = tmp_path / "minifig_counts_by_set.csv"
+    destination_path = tmp_path / "figures" / "step20" / "minifigs_per_set.png"
+    counts_path.write_text(
+        "set_num,set_id,name,year,minifig_count\n"
+        "123-1,123,Set A,2020,2\n"
+        "124-1,124,Set B,2021,1\n"
+    )
+
+    plot_minifigs_per_set(counts_path, destination_path)
+
+    assert destination_path.exists()
+    assert destination_path.stat().st_size > 0