From 1c19b83d611ef789d5d513f357abc12d3057af51 Mon Sep 17 00:00:00 2001
From: Martin Lehmann <martin.lehmann@deutschebahn.com>
Date: Tue, 17 Oct 2023 17:19:20 +0200
Subject: [PATCH] fix(metrics): Don't crash if there are no diagrams or
 semantic objects

---
 capellambse/extensions/metrics/composer.py | 5 ++++-
 tests/test_aird_parser.py                  | 9 +++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/capellambse/extensions/metrics/composer.py b/capellambse/extensions/metrics/composer.py
index 02fd4cf4c..a4a4a2637 100644
--- a/capellambse/extensions/metrics/composer.py
+++ b/capellambse/extensions/metrics/composer.py
@@ -145,7 +145,10 @@ def draw_labeled_bar(
 ) -> str:
     """Construct a bar with label and icon (SVG string)."""
     total = sum(segments)
-    normalized_segments = [x / total for x in segments]
+    if total:
+        normalized_segments = [x / total for x in segments]
+    else:
+        normalized_segments = [0 for _ in segments]
     return (
         draw_icon(x, y)
         + draw_text(x + 5, y + 3, f"{total}")
diff --git a/tests/test_aird_parser.py b/tests/test_aird_parser.py
index 63e6fa1e0..bafe17469 100644
--- a/tests/test_aird_parser.py
+++ b/tests/test_aird_parser.py
@@ -10,6 +10,10 @@
 import capellambse
 from capellambse import aird, diagram, loader
 
+EMPTY_MODEL = pathlib.Path(__file__).parent.joinpath(
+    "data/decl/empty_project_52/empty_project_52.aird"
+)
+
 
 class TestAIRDBasicFunctionality:
     test_model = (
@@ -81,6 +85,11 @@ def test_python_code_representation_matches_expected_output(
         actual = repr(diagram_under_test)
         assert actual == expected
 
+    def test_enumerate_diagrams_doesnt_crash_if_there_are_no_diagrams(self):
+        model = loader.MelodyLoader(EMPTY_MODEL)
+        for _ in aird.enumerate_diagrams(model):
+            pass
+
 
 def test_airdparser_msm_produces_valid_json_without_error(
     model: capellambse.MelodyModel,