From 16a5a2a2c8d8dbf9cc3e033dd84b986bcaadb963 Mon Sep 17 00:00:00 2001
From: Joshua Cannon <joshua.cannon@ni.com>
Date: Fri, 4 Jan 2019 14:03:53 -0600
Subject: Fixed #30076 -- Added Model.get_FOO_display() even if field's choices
 are empty.

---
 tests/model_fields/models.py | 16 +++++++++++++
 tests/model_fields/tests.py  | 55 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 70 insertions(+), 1 deletion(-)

(limited to 'tests/model_fields')

diff --git a/tests/model_fields/models.py b/tests/model_fields/models.py
index 13d4843632..02fea36b31 100644
--- a/tests/model_fields/models.py
+++ b/tests/model_fields/models.py
@@ -50,6 +50,14 @@ class Whiz(models.Model):
     c = models.IntegerField(choices=CHOICES, null=True)
 
 
+class WhizDelayed(models.Model):
+    c = models.IntegerField(choices=(), null=True)
+
+
+# Contrived way of adding choices later.
+WhizDelayed._meta.get_field('c').choices = Whiz.CHOICES
+
+
 class WhizIter(models.Model):
     c = models.IntegerField(choices=iter(Whiz.CHOICES), null=True)
 
@@ -58,6 +66,14 @@ class WhizIterEmpty(models.Model):
     c = models.CharField(choices=iter(()), blank=True, max_length=1)
 
 
+class Choiceful(models.Model):
+    no_choices = models.IntegerField(null=True)
+    empty_choices = models.IntegerField(choices=(), null=True)
+    with_choices = models.IntegerField(choices=[(1, 'A')], null=True)
+    empty_choices_bool = models.BooleanField(choices=())
+    empty_choices_text = models.TextField(choices=())
+
+
 class BigD(models.Model):
     d = models.DecimalField(max_digits=32, decimal_places=30)
 
diff --git a/tests/model_fields/tests.py b/tests/model_fields/tests.py
index 42e784db54..f55175aa9e 100644
--- a/tests/model_fields/tests.py
+++ b/tests/model_fields/tests.py
@@ -1,12 +1,14 @@
 import pickle
 
 from django import forms
+from django.core.exceptions import ValidationError
 from django.db import models
 from django.test import SimpleTestCase, TestCase
 from django.utils.functional import lazy
 
 from .models import (
-    Bar, Foo, RenamedField, VerboseNameField, Whiz, WhizIter, WhizIterEmpty,
+    Bar, Choiceful, Foo, RenamedField, VerboseNameField, Whiz, WhizDelayed,
+    WhizIter, WhizIterEmpty,
 )
 
 
@@ -103,6 +105,51 @@ class BasicFieldTests(SimpleTestCase):
 
 class ChoicesTests(SimpleTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.no_choices = Choiceful._meta.get_field('no_choices')
+        cls.empty_choices = Choiceful._meta.get_field('empty_choices')
+        cls.empty_choices_bool = Choiceful._meta.get_field('empty_choices_bool')
+        cls.empty_choices_text = Choiceful._meta.get_field('empty_choices_text')
+        cls.with_choices = Choiceful._meta.get_field('with_choices')
+
+    def test_choices(self):
+        self.assertIsNone(self.no_choices.choices)
+        self.assertEqual(self.empty_choices.choices, ())
+        self.assertEqual(self.with_choices.choices, [(1, 'A')])
+
+    def test_flatchoices(self):
+        self.assertEqual(self.no_choices.flatchoices, [])
+        self.assertEqual(self.empty_choices.flatchoices, [])
+        self.assertEqual(self.with_choices.flatchoices, [(1, 'A')])
+
+    def test_check(self):
+        self.assertEqual(Choiceful.check(), [])
+
+    def test_invalid_choice(self):
+        model_instance = None  # Actual model instance not needed.
+        self.no_choices.validate(0, model_instance)
+        msg = "['Value 99 is not a valid choice.']"
+        with self.assertRaisesMessage(ValidationError, msg):
+            self.empty_choices.validate(99, model_instance)
+        with self.assertRaisesMessage(ValidationError, msg):
+            self.with_choices.validate(99, model_instance)
+
+    def test_formfield(self):
+        no_choices_formfield = self.no_choices.formfield()
+        self.assertIsInstance(no_choices_formfield, forms.IntegerField)
+        fields = (
+            self.empty_choices, self.with_choices, self.empty_choices_bool,
+            self.empty_choices_text,
+        )
+        for field in fields:
+            with self.subTest(field=field):
+                self.assertIsInstance(field.formfield(), forms.ChoiceField)
+
+
+class GetFieldDisplayTests(SimpleTestCase):
+
     def test_choices_and_field_display(self):
         """
         get_choices() interacts with get_FIELD_display() to return the expected
@@ -113,6 +160,7 @@ class ChoicesTests(SimpleTestCase):
         self.assertEqual(Whiz(c=9).get_c_display(), 9)          # Invalid value
         self.assertIsNone(Whiz(c=None).get_c_display())         # Blank value
         self.assertEqual(Whiz(c='').get_c_display(), '')        # Empty value
+        self.assertEqual(WhizDelayed(c=0).get_c_display(), 'Other')  # Delayed choices
 
     def test_iterator_choices(self):
         """
@@ -135,6 +183,11 @@ class ChoicesTests(SimpleTestCase):
 
 class GetChoicesTests(SimpleTestCase):
 
+    def test_empty_choices(self):
+        choices = []
+        f = models.CharField(choices=choices)
+        self.assertEqual(f.get_choices(include_blank=False), choices)
+
     def test_blank_in_choices(self):
         choices = [('', '<><>'), ('a', 'A')]
         f = models.CharField(choices=choices)
-- 
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