{"id":1110,"date":"2020-10-19T01:24:24","date_gmt":"2020-10-19T01:24:24","guid":{"rendered":"http:\/\/10.0.0.14\/?p=1110"},"modified":"2021-09-07T23:32:01","modified_gmt":"2021-09-07T23:32:01","slug":"tdd-with-django-graphene-docker-part-4","status":"publish","type":"post","link":"https:\/\/tutorials.leesonresearch.com\/tutorials\/2020\/10\/19\/tdd-with-django-graphene-docker-part-4\/","title":{"rendered":"TDD with Gatsby, Django & Docker Part 1, Chapter 04 — Mutations"},"content":{"rendered":"\n
Mutations<\/h2>\n\n\n\n
In order to post data to a server with Graphql we use a process called mutations which are similar to the query process we defined in our last post.<\/p>\n\n\n\n
TDD Graphene Mutations<\/h4>\n\n\n\n
We’ll begin by writing a test for creating a new todo item.<\/p>\n\n\n\n
Create a new file server\/todo_app\/tests\/test_graphql_mutations.py:<\/p>\n\n\n
#1: Define a mutation class, define the resulting output of the mutation which is the data the server sends back to the client.<\/li>
#2: Define the arguments that the server is expecting.<\/li>
#3: Define the mutation method that creates a new task in the database with the data the user sent. After the server returns the CreateTask class with our new data which matches the parameters in #1.<\/li>
#4: Create a mutation class with the field to be resolved.<\/li><\/ul>\n\n\n\n
Your updated server\/todo_app\/schema.py should be as follows:<\/p>\n\n\n
If your test fails you can always run pytest in verbose mode with the -vv flag:<\/p>\n\n\n
\ndocker-compose run server pytest -vv\n<\/pre><\/div>\n\n\n
In verbose mode pytest may tell you:<\/p>\n\n\n
\n\/usr\/local\/lib\/python3.8\/site-packages\/graphene_django\/utils\/testing.py:112: in assertResponseNoErrors\n self.assertEqual(resp.status_code, 200)\nE AssertionError: 400 != 200\n<\/pre><\/div>\n\n\n
… which is not much, other than your mutation has an error somewhere<\/em> in the code. In which case you can add another level of granularity to our mutation test using assert content == to an expected result. <\/p>\n\n\n
I will go this extra mile if I do get the AssertionError: 400 != 200 error in which case the assert content == expected proves most helpful in tracking down the problem in the verbose test result.<\/p>\n\n\n\n
Complete Schema & Tests for All Crud Operations<\/h4>\n\n\n\n
We have the create operation for creating a todo but, now we need update and delete operations for both the schema and mutation tests which following in the same vein as our create todo mutation.<\/p>\n\n\n\n
We also need to extend our schema and tests for all the crud operations for the Project and Category models.<\/p>\n\n\n\n
Again we’ll start with tests. Below are tests for the crud operations of all our models:<\/p>\n\n\n
Running these tests will throw multiple errors which clarifies our thinking in the sense that pytest is telling us what object types, fields and resolvers we need to add to our schema.<\/p>\n\n\n\n
The following is a complete update of the todo app schema which should enable us to pass all our tests:<\/p>\n\n\n
\n# server\/todo_app\/schema.py\n\nimport graphene\nfrom graphene import Schema\nfrom graphene_django import DjangoObjectType\nfrom graphql import GraphQLError\nfrom todo_app.models import Todo, Project, Category\n\nclass TodoType(DjangoObjectType):\n class Meta:\n model = Todo\n\nclass ProjectType(DjangoObjectType):\n class Meta:\n model = Project\n\nclass CategoryType(DjangoObjectType):\n class Meta:\n model = Category\n\nclass Query(graphene.ObjectType):\n \n # todo queries\n todos = graphene.List(TodoType)\n def resolve_todos(self, info, **kwargs):\n return Todo.objects.all()\n\n todo = graphene.Field(\n TodoType,\n id=graphene.Int(),\n ) \n def resolve_todo(self, info, id):\n return Todo.objects.get(pk=id)\n\n # project queries\n projects = graphene.List(ProjectType)\n def resolve_projects(self, info, **kwargs):\n return Project.objects.all()\n\n project = graphene.Field(\n ProjectType,\n id=graphene.Int(),\n )\n def resolve_project(self, info, id):\n return Project.objects.get(pk=id)\n\n # category queries\n categories = graphene.List(CategoryType)\n def resolve_categories(self, info, **kwargs):\n return Category.objects.all()\n\n category = graphene.Field(\n CategoryType,\n id=graphene.Int(),\n )\n def resolve_category(self, info, id):\n return Category.objects.get(pk=id)\n\n# Mutations\nclass CreateTodo(graphene.Mutation):\n id = graphene.Int()\n title = graphene.String()\n task = graphene.String()\n is_completed = graphene.Boolean()\n slug = graphene.String()\n project = graphene.Field(ProjectType)\n category = graphene.Field(CategoryType)\n\n class Arguments:\n title = graphene.String()\n task = graphene.String()\n projId = graphene.Int()\n catId = graphene.Int()\n\n def mutate(self, info, title, task, projId, catId):\n proj = Project.objects.get(pk=projId)\n\n cat = Category.objects.get(pk=catId)\n \n todo = Todo.objects.create(\n title=title, \n task=task, \n project=proj, \n category=cat,\n )\n\n return CreateTodo(\n id=todo.id,\n title=todo.title,\n task=todo.task,\n slug=todo.slug,\n project=todo.project,\n category=todo.category,\n )\n\nclass DeleteTodo(graphene.Mutation):\n id = graphene.Int()\n title = graphene.String()\n ok = graphene.Boolean()\n\n class Arguments:\n id = graphene.Int()\n\n def mutate(self, info, id=id):\n todo = Todo.objects.get(pk=id)\n\n if todo:\n todo.delete()\n return DeleteTodo(\n id = todo.id,\n title = todo.title,\n ok = True\n )\n\nclass UpdateTodo(graphene.Mutation):\n id = graphene.Int()\n title = graphene.String()\n task = graphene.String()\n is_completed = graphene.Boolean()\n project = graphene.Field(ProjectType)\n category = graphene.Field(CategoryType)\n slug = graphene.String()\n\n class Arguments:\n id = graphene.Int()\n title = graphene.String()\n task = graphene.String()\n is_completed = graphene.Boolean()\n projId = graphene.Int()\n catId = graphene.Int()\n\n def mutate(self, info, id, title=None, task=None, is_completed=None, projId=None, catId=None):\n todo = Todo.objects.get(pk=id)\n if projId:\n project = Project.objects.get(pk=projId)\n if not project:\n raise Exception('There is no project with this id.')\n\n if catId:\n category = Category.objects.get(pk=catId)\n if not category:\n raise Exception('No category with this id exists.')\n\n if todo:\n if title:\n todo.title = title\n if task:\n todo.task = task\n if is_completed:\n todo.is_completed = is_completed\n if projId:\n todo.project = project\n if catId:\n todo.category = category\n\n todo.save()\n\n return UpdateTodo(\n id = todo.id,\n title = todo.title,\n task = todo.task,\n is_completed = todo.is_completed,\n project = todo.project,\n category = todo.category,\n slug = todo.slug,\n )\n else:\n raise Exception('There is no todo with this id.')\n\nclass CreateProject(graphene.Mutation):\n id = graphene.Int()\n name = graphene.String()\n description = graphene.String()\n slug = graphene.String()\n\n class Arguments:\n name = graphene.String()\n description = graphene.String()\n\n def mutate(self, info, name, description=None):\n project = Project.objects.create(name=name, description=description)\n\n return CreateProject(\n id = project.id,\n name = project.name,\n description = project.description,\n slug = project.slug\n )\n\nclass DeleteProject(graphene.Mutation):\n id = graphene.Int()\n name = graphene.String()\n ok = graphene.Boolean()\n\n class Arguments:\n id = graphene.Int()\n\n def mutate(self, info, id=id):\n project = Project.objects.get(pk=id)\n\n if project:\n project.delete()\n return DeleteProject(\n id = project.id,\n name = project.name,\n ok = True,\n )\n\nclass UpdateProject(graphene.Mutation):\n id = graphene.Int()\n name = graphene.String()\n description = graphene.String()\n slug = graphene.String()\n\n class Arguments:\n id = graphene.Int()\n name = graphene.String()\n description = graphene.String()\n \n def mutate(self, info, id=id, name=None, description=None):\n project = Project.objects.get(pk=id)\n\n if project:\n if name:\n project.name = name\n if description:\n project.description = description\n\n project.save()\n\n return UpdateProject(\n id = project.id,\n name = project.name,\n description = project.description,\n slug = project.slug, \n )\n else:\n raise Exception('There is no project with this id.')\n\nclass CreateCategory(graphene.Mutation):\n id = graphene.Int()\n name = graphene.String()\n slug = graphene.String()\n parent = graphene.Field(CategoryType)\n\n class Arguments:\n name = graphene.String()\n parentId = graphene.Int()\n\n def mutate(self, info, name, parentId=None):\n\n if parentId:\n parent = Category.objects.get(pk=parentId)\n category = Category.objects.create(name=name, parent=parent)\n else:\n category = Category.objects.create(name=name)\n\n return CreateCategory(\n id=category.id,\n name=category.name,\n slug=category.slug,\n parent=category.parent,\n )\n\nclass DeleteCategory(graphene.Mutation):\n id = graphene.Int()\n name = graphene.String()\n slug = graphene.String()\n ok = graphene.Boolean()\n\n class Arguments:\n id = graphene.Int()\n\n def mutate(self, info, id=id):\n\n category = Category.objects.get(pk=id)\n if category:\n category.delete()\n return DeleteCategory(\n id = category.id,\n name = category.name,\n slug = category.slug,\n ok = True\n )\n\nclass UpdateCategory(graphene.Mutation):\n id = graphene.Int()\n name = graphene.String()\n parent = graphene.Field(CategoryType)\n slug = graphene.String()\n\n class Arguments:\n id = graphene.Int()\n name = graphene.String()\n parentId = graphene.Int()\n\n def mutate(self, info, id, name=None, parentId=None):\n category = Category.objects.get(pk=id)\n\n if parentId:\n parent = Category.objects.get(pk=parentId)\n if not parent:\n raise Exception('No category with this id to be used as the updated parent.')\n\n\n if category:\n if name:\n category.name = name\n if parentId:\n category.parent = parent\n \n category.save()\n\n return UpdateCategory(\n id = category.id,\n name = category.name,\n parent = category.parent,\n slug = category.slug,\n )\n else:\n raise Exception('No category with this id.') \n\n\n\nclass Mutation(graphene.ObjectType):\n create_todo = CreateTodo.Field()\n update_todo = UpdateTodo.Field()\n delete_todo = DeleteTodo.Field()\n create_project = CreateProject.Field()\n delete_project = DeleteProject.Field()\n update_project = UpdateProject.Field()\n create_category = CreateCategory.Field()\n delete_category = DeleteCategory.Field()\n update_category = UpdateCategory.Field()\n\nschema = Schema(query=Query, mutation=Mutation)\n<\/pre><\/div>\n\n\n
Running my tests…<\/p>\n\n\n
\ndocker-compose run server pytest\n<\/pre><\/div>\n\n\n<\/figure>\n\n\n\n
… all 30 of my tests passed. This gives me enormous confidence moving forward with this project.<\/p>\n\n\n\n
Next post we add java web token, JWT, user authentication allowing only an authenticated user to create, edit and delete their project todos.<\/p>\n\n\n\n
![\"\"](\"http:\/\/10.0.0.14\/wp-content\/uploads\/2020\/10\/pytest_result-1024x298.png\")
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