Improve test coverage.

model_clone/mixins/clone.py

@@ -508,7 +508,12 @@ def __duplicate_m2m_fields(self, duplicate, sub_clone):
                 objs = through.objects.filter(**{field_name: self.pk})
                 for item in objs:
                     if hasattr(through, "make_clone"):
-                        item.make_clone(attrs={field_name: duplicate}, sub_clone=True)
+                        try:
+                            item.make_clone(attrs={field_name: duplicate})
+                        except IntegrityError:
+                            item.make_clone(
+                                attrs={field_name: duplicate}, sub_clone=True
+                            )
                     else:
                         item.pk = None
                         setattr(item, field_name, duplicate)

model_clone/tests/test_clone_mixin.py

@@ -22,7 +22,9 @@
     Cover,
     BackCover,
     BookTag,
+    BookSaleTag,
     Tag,
+    SaleTag,
 )
 
 User = get_user_model()
@@ -234,6 +236,24 @@ def test_cloning_with_explicit_clone_m2m_fields(
             list(book_clone_2.tags.values_list("name")),
         )
 
+        sale_tag_1 = SaleTag.objects.create(name="test-tag-3")
+        sale_tag_2 = SaleTag.objects.create(name="test-tag-4")
+
+        _clone_m2m_fields_mock.return_value = ["sale_tags"]
+
+        book_3 = Book.objects.create(
+            name="New Book 3", created_by=self.user1, slug=slugify("New Book 3")
+        )
+        BookSaleTag.objects.create(book=book_3, sale_tag=sale_tag_1)
+        BookSaleTag.objects.create(book=book_3, sale_tag=sale_tag_2)
+
+        book_clone_3 = book_3.make_clone()
+
+        self.assertEqual(
+            list(book_3.sale_tags.values_list("name")),
+            list(book_clone_3.sale_tags.values_list("name")),
+        )
+
     @patch("sample.models.Author._clone_excluded_fields", new_callable=PropertyMock)
     def test_cloning_with_clone_excluded_fields(
         self,

sample/migrations/0015_auto_20210423_0935.py

@@ -0,0 +1,71 @@
+# Generated by Django 3.2 on 2021-04-23 09:35
+
+from django.db import migrations, models
+import django.db.models.deletion
+import model_clone.mixins.clone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("sample", "0014_auto_20210422_1449"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="SaleTag",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("name", models.CharField(max_length=255)),
+            ],
+            options={
+                "abstract": False,
+            },
+            bases=(model_clone.mixins.clone.CloneMixin, models.Model),
+        ),
+        migrations.CreateModel(
+            name="BookSaleTag",
+            fields=[
+                (
+                    "id",
+                    models.BigAutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                (
+                    "book",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE, to="sample.book"
+                    ),
+                ),
+                (
+                    "sale_tag",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.PROTECT, to="sample.saletag"
+                    ),
+                ),
+            ],
+            options={
+                "unique_together": {("book", "sale_tag")},
+            },
+            bases=(model_clone.mixins.clone.CloneMixin, models.Model),
+        ),
+        migrations.AddField(
+            model_name="book",
+            name="sale_tags",
+            field=models.ManyToManyField(
+                through="sample.BookSaleTag", to="sample.SaleTag"
+            ),
+        ),
+    ]

sample/models.py

@@ -42,6 +42,13 @@ def __str__(self):
         return _(self.name)
 
 
+class SaleTag(CloneModel):
+    name = models.CharField(max_length=255)
+
+    def __str__(self):
+        return _(self.name)
+
+
 class Book(CloneModel):
     name = models.CharField(max_length=2000)
     slug = models.SlugField(unique=True)
@@ -52,6 +59,7 @@ class Book(CloneModel):
     )
     created_at = models.DateTimeField(auto_now_add=True)
     tags = models.ManyToManyField(Tag, through="BookTag")
+    sale_tags = models.ManyToManyField(SaleTag, through="BookSaleTag")
 
     def __str__(self):
         return _(self.name)
@@ -67,6 +75,16 @@ class Meta:
         ]
 
 
+class BookSaleTag(CloneModel):
+    book = models.ForeignKey(Book, on_delete=models.CASCADE)
+    sale_tag = models.ForeignKey(SaleTag, on_delete=models.PROTECT)
+
+    class Meta:
+        unique_together = [
+            ("book", "sale_tag"),
+        ]
+
+
 class Page(CloneModel):
     content = models.CharField(max_length=20000)
     book = models.ForeignKey(Book, on_delete=models.CASCADE)