Add support for many-to-many relationships with through tables

milkman/dairy.py

@@ -66,6 +66,9 @@ def deliver(self, the_milkman, **explicit_values):
     def is_m2m(self, field):
         return field in [f.name for f in self.model_class._meta.local_many_to_many]
 
+    def has_explicit_through_table(self, field):
+        return not field.rel.through._meta.auto_created
+
     def set_explicit_values(self, target, explicit_values):
         for k,v in explicit_values.iteritems():
             if not self.is_m2m(k):
@@ -86,7 +89,8 @@ def set_local_fields(self, target, the_milkman, exclude):
 
     def set_m2m_fields(self, target, the_milkman, exclude):
         for field in self.fields_to_generate(self.model_class._meta.local_many_to_many, exclude):
-            setattr(target, field.name, [the_milkman.deliver(field.rel.to)])
+            if not self.has_explicit_through_table(field):
+                setattr(target, field.name, [the_milkman.deliver(field.rel.to)])
 
     def generator_for(self, registry, field):
         field_cls = type(field)

testapp/models.py

@@ -52,4 +52,4 @@ class CounselingUncle(models.Model):
 
 class EstrangedChild(models.Model):
     name = models.CharField(max_length=16)
-    cousins = models.ManyToManyField(Uncle, through=CounselingUncle)
+    uncles = models.ManyToManyField(Uncle, through=CounselingUncle)

testapp/tests.py

@@ -47,6 +47,26 @@ def test_m2m_explicit(self):
         aunt = milkman.deliver(Aunt, uncles=[uncle])
         self.assertEquals(uncle, aunt.uncles.all()[0])
 
+    def test_m2m_through_model(self):
+        couseling_uncle = milkman.deliver(CounselingUncle)
+        self.assertTrue(isinstance(couseling_uncle, CounselingUncle))
+        self.assertEquals(couseling_uncle.cousin.uncles.all().count(), 1)
+        self.assertTrue(len(couseling_uncle.cousin.name) > 0)
+        self.assertTrue(len(couseling_uncle.uncle.name) > 0)
+
+    def test_m2m_model(self):
+        child = milkman.deliver(EstrangedChild)
+        self.assertTrue(isinstance(child, EstrangedChild))
+        self.assertEquals(child.uncles.all().count(), 0)
+        self.assertTrue(len(child.name) > 0)
+
+    def test_m2m_model_explicit_add(self):
+        child = milkman.deliver(EstrangedChild)
+        couseling_uncle = milkman.deliver(CounselingUncle, cousin=child)
+        self.assertTrue(isinstance(child, EstrangedChild))
+        self.assertEquals(child.uncles.all().count(), 1)
+        self.assertTrue(len(child.name) > 0)
+
 class RandomFieldTest(unittest.TestCase):
     def test_required_field(self):
         root = milkman.deliver(Root)
@@ -116,11 +136,3 @@ def test_timefield_maker(self):
         times = v.split(':')
         self.assertEquals(len(times), 3)
 
-class ManyToManyThroughTest(unittest.TestCase):
-    def test_through_model(self):
-        uncle = milkman.deliver(CounselingUncle)
-        self.assertTrue(isinstance(uncle, CounselingUncle))
-
-    def test_model(self):
-        child = milkman.deliver(EstrangedChild)
-        self.assertTrue(isinstance(child, EstrangedChild))