Merge pull request #398 from git-big-picture/more-deterministic-graph…

…viz-output

More deterministic Graphviz output

git_big_picture/_main.py

@@ -1036,7 +1036,7 @@ def label_gen():
         if history_direction is not None:
             rankdir = RANKDIR_OF_HISTORY_DIRECTION[history_direction]
             dot_file_lines.append(f'\trankdir="{rankdir}";')
-        for sha_one, labels, color in label_gen():
+        for sha_one, labels, color in sorted(label_gen()):
             label = '\\n'.join(labels + ((with_commit_messages or sha_ones_on_labels) and [
                 format_label(sha_one),
             ] or list()))
@@ -1051,7 +1051,7 @@ def label_gen():
                 sha_label = format_label(sha_one)
                 dot_file_lines.append(f'\t"{sha_one}"[label="{sha_label}"];')
         for child, self.parents in self.parents.items():
-            for p in self.parents:
+            for p in sorted(self.parents):
                 dot_file_lines.append(f'\t"{child}" -> "{p}";')
         dot_file_lines.append('}')
         return dot_file_lines

run-tests-with-coverage.sh

@@ -68,6 +68,22 @@ except ImportError:
     pass
 SITECUSTOMIZE_PY_EOF
 
+# Run smoke-test for determinism with real Git history;
+# these modes are opposites of FILTER_DEFAULTS in _main.py .
+for mode in \
+        --all \
+        --no-branches \
+        --no-tags \
+        --no-roots \
+        --merges \
+        --bifurcations \
+        --commit-messages \
+        ; do
+    git-big-picture --graphviz "${mode}" "${source_dir}" > 1.dot
+    git-big-picture --graphviz "${mode}" "${source_dir}" > 2.dot
+    diff -U 0 1.dot 2.dot  # i.e. fail if there is any diff
+    rm 1.dot 2.dot
+done
 
 # Actually run the tests
 exit_code=0