Django code

Module.py

from django.db import models 
# Create your models here.
class Item(models.Model):
	id =models.AutoField(primary_key=True)
	name=models.CharField(max_length=250)
	category=models.CharField(max_length=250)
	price=models.IntegerField()
	quantity=models.IntegerField()
	barcode=models. IntegerField (unique=True)

serializers.py

from rest_framework import serializers
from .models import Item
#Create your serializers here.
class ItemSerializer(serializers.ModelSerializer):
	class Meta:
	    model = Item
	    fields = '__all__'

views.py

from rest_framework import viewsets
from rest_framework.views import APIView
from rest_framework.response import Response
from inventoryapp.serializers import ItemSerializer
from .models import Item
from rest_framework import status

# Create your views here

class SortItemsView(APIView):
    def get(self, request):
        items = Item.objects.all().order_by('-price')
        serializer = ItemSerializer(items, many=True)
        return Response(serializer.data)

class QueryItemsView(APIView):
    def get(self, request, category):
        items = Item.objects.filter(category=category)
        serializer = ItemSerializer(items, many=True)
        return Response(serializer.data)

class InventoryItemView(APIView):
    def get(self, request):
        items = Item.objects.all()
        serializer = ItemSerializer(items, many=True)
        return Response(serializer.data)

    def post(self, request):
        serializer = ItemSerializer(data=request.data)
        if serializer.is_valid():
            barcode = serializer.validated_data['barcode']
            if Item.objects.filter(barcode=barcode).exists():
                return Response({'barcode': ['item with this barcode already exists']}, status=status.HTTP_400_BAD_REQUEST)
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    def delete(self, request, pk):
        try:
            item = Item.objects.get(pk=pk)
        except Item.DoesNotExist:
            return Response(status=status.HTTP_404_NOT_FOUND)
        item.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

urls.py

"""inventoryapi URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/1.8/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  url(r'^$', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  url(r'^$', Home.as_view(), name='home')
Including another URLconf
    1. Add an import:  from blog import urls as blog_urls
    2. Add a URL to urlpatterns:  url(r'^blog/', include(blog_urls))
"""

from django.urls import include, path
from django.contrib import admin
from inventoryapp.views import InventoryItemView, SortItemsView, QueryItemsView

# Add your URLS in respective place.

urlpatterns = [
    path('admin/', admin.site.urls),
    path('inventory/items/', InventoryItemView.as_view(), name='inventory-item'),
    path('inventory/items/<int:pk>/', InventoryItemView.as_view(), name='inventory-detail'),
    path('items/sort/', SortItemsView.as_view(), name='sort-items'),
    path('items/query/<str:category>/', QueryItemsView.as_view(), name='query-items'),
]

admin.py

from django.contrib import admin
from .models import Item

# Register your models here.

admin.site.register(Item)

Run Steps

python3 -m pip install -r requirements.txt

python3 manage.py makemigrations

python3 manage.py migrate --run-syncdb

python3 manage.py runserver

ctrl +c

sh run.sh

ctrl +c

sh install.sh

sh test.sh

tests.py

from django.test import TestCase

# Create your tests here.
class AppTest(TestCase):

    def test_1_inventory_get_success(self):
        res=self.client.get('/inventory/items/')
        print(res.json())
        assert b'[]' in res.content
        assert 200==res.status_code

    def test_2_inventory_post_success(self):
        res=self.client.post('/inventory/items/',data={'name':'shirt','category':'top wear','price':700,'discount':20,'quantity':2,'barcode':123456})
        print(res.json())
        assert 'shirt' == res.json()['name']
        assert 201==res.status_code


    def test_3_inventory_delete_success(self):
        res=self.client.post('/inventory/items/',data={'name':'shirt','category':'top wear','price':700,'discount':20,'quantity':2,'barcode':123456})
        res=self.client.delete('/inventory/items/1/')
        assert 204==res.status_code

    
    def test_4_inventory_post_error(self):
        
        res=self.client.post('/inventory/items/',data={'name':'shirt','category':'top wear','price':700,'discount':20,'quantity':2,'barcode':123456})
        res=self.client.post('/inventory/items/',data={'name':'t-shirt','category':'top wear','price':1300,'discount':30,'quantity':2,'barcode':123456})
        print(res.json())
        assert b'inventory with this barcode already exists' in res.content
        assert 400==res.status_code


    def test_5_inventory_get_sort_success(self):
        res=self.client.post('/inventory/items/',data={'name':'shirt','category':'top wear','price':700,'discount':20,'quantity':2,'barcode':123456})
        res=self.client.post('/inventory/items/',data={'name':'t-shirt','category':'top wear','price':1300,'discount':30,'quantity':2,'barcode':12345687})
        response=self.client.get('/items/sort/')
        print(response.json())
        assert 1300==response.json()[0]['price']
        assert 700==response.json()[1]['price']
        assert 200==response.status_code

    def test_6_inventory_get_query_category_success(self):
        res=self.client.post('/inventory/items/',data={'name':'shirt','category':'top wear','price':700,'discount':20,'quantity':2,'barcode':123456})
        res=self.client.post('/inventory/items/',data={'name':'t-shirt','category':'top wear','price':1300,'discount':30,'quantity':2,'barcode':12345687})  
        res=self.client.post('/inventory/items/',data={'name':'shorts','category':'bottom wear','price':300,'discount':5,'quantity':3,'barcode':123455})
        response=self.client.get('/items/query/top%20wear/')
        print(response.json())
        
        assert 'shirt' in response.json()[0]['name']
        assert 't-shirt' in response.json()[1]['name']
        assert 200==response.status_code
        assert len(response.json())==2