tests: Improve type coverage

Based on graphql#2609

src/__testUtils__/__tests__/genFuzzStrings-test.js

@@ -5,7 +5,10 @@ import { describe, it } from 'mocha';
 
 import genFuzzStrings from '../genFuzzStrings';
 
-function expectFuzzStrings(options) {
+function expectFuzzStrings(options: {|
+  allowedChars: Array<string>,
+  maxLength: number,
+|}) {
   return expect(Array.from(genFuzzStrings(options)));
 }
 

src/__tests__/starWarsData.js

@@ -1,5 +1,35 @@
 // @flow strict
 
+/**
+ * These are types which correspond to the schema.
+ * They represent the shape of the data visited during field resolution.
+ */
+export type Character = {
+  id: string,
+  name: string,
+  friends: Array<string>,
+  appearsIn: Array<number>,
+  ...
+};
+
+export type Human = {|
+  type: 'Human',
+  id: string,
+  name: string,
+  friends: Array<string>,
+  appearsIn: Array<number>,
+  homePlanet?: string,
+|};
+
+export type Droid = {|
+  type: 'Droid',
+  id: string,
+  name: string,
+  friends: Array<string>,
+  appearsIn: Array<number>,
+  primaryFunction: string,
+|};
+
 /**
  * This defines a basic set of data for our Star Wars Schema.
  *
@@ -8,7 +38,7 @@
  * JSON objects in a more complex demo.
  */
 
-const luke = {
+const luke: Human = {
   type: 'Human',
   id: '1000',
   name: 'Luke Skywalker',
@@ -17,7 +47,7 @@ const luke = {
   homePlanet: 'Tatooine',
 };
 
-const vader = {
+const vader: Human = {
   type: 'Human',
   id: '1001',
   name: 'Darth Vader',
@@ -26,15 +56,15 @@ const vader = {
   homePlanet: 'Tatooine',
 };
 
-const han = {
+const han: Human = {
   type: 'Human',
   id: '1002',
   name: 'Han Solo',
   friends: ['1000', '1003', '2001'],
   appearsIn: [4, 5, 6],
 };
 
-const leia = {
+const leia: Human = {
   type: 'Human',
   id: '1003',
   name: 'Leia Organa',
@@ -43,23 +73,23 @@ const leia = {
   homePlanet: 'Alderaan',
 };
 
-const tarkin = {
+const tarkin: Human = {
   type: 'Human',
   id: '1004',
   name: 'Wilhuff Tarkin',
   friends: ['1001'],
   appearsIn: [4],
 };
 
-const humanData = {
+const humanData: {| [id: string]: Human |} = {
   '1000': luke,
   '1001': vader,
   '1002': han,
   '1003': leia,
   '1004': tarkin,
 };
 
-const threepio = {
+const threepio: Droid = {
   type: 'Droid',
   id: '2000',
   name: 'C-3PO',
@@ -68,7 +98,7 @@ const threepio = {
   primaryFunction: 'Protocol',
 };
 
-const artoo = {
+const artoo: Droid = {
   type: 'Droid',
   id: '2001',
   name: 'R2-D2',
@@ -77,47 +107,20 @@ const artoo = {
   primaryFunction: 'Astromech',
 };
 
-const droidData = {
+const droidData: {| [id: string]: Droid |} = {
   '2000': threepio,
   '2001': artoo,
 };
 
-/**
- * These are Flow types which correspond to the schema.
- * They represent the shape of the data visited during field resolution.
- */
-export type Character = {
-  id: string,
-  name: string,
-  friends: Array<string>,
-  appearsIn: Array<number>,
-  ...
-};
-
-export type Human = {|
-  type: 'Human',
-  id: string,
-  name: string,
-  friends: Array<string>,
-  appearsIn: Array<number>,
-  homePlanet: string,
-|};
-
-export type Droid = {|
-  type: 'Droid',
-  id: string,
-  name: string,
-  friends: Array<string>,
-  appearsIn: Array<number>,
-  primaryFunction: string,
-|};
-
 /**
  * Helper function to get a character by ID.
  */
-function getCharacter(id) {
+function getCharacter(id: string): Promise<Character> {
+  const character = humanData[id] ?? droidData[id];
   // Returning a promise just to illustrate that GraphQL.js supports it.
-  return Promise.resolve(humanData[id] ?? droidData[id]);
+  return character !== undefined
+    ? Promise.resolve(character)
+    : Promise.reject(new Error(`Unknown character id: ${id}.`));
 }
 
 /**

src/__tests__/starWarsIntrospection-test.js

@@ -7,7 +7,7 @@ import { graphqlSync } from '../graphql';
 
 import { StarWarsSchema } from './starWarsSchema';
 
-function queryStarWars(source) {
+function queryStarWars(source: string) {
   const result = graphqlSync({ schema: StarWarsSchema, source });
   expect(Object.keys(result)).to.deep.equal(['data']);
   return result.data;

src/__tests__/starWarsValidation-test.js

@@ -13,7 +13,7 @@ import { StarWarsSchema } from './starWarsSchema';
 /**
  * Helper function to test a query and the expected response.
  */
-function validationErrors(query) {
+function validationErrors(query: string) {
   const source = new Source(query, 'StarWars.graphql');
   const ast = parse(source);
   return validate(StarWarsSchema, ast);

src/execution/__tests__/abstract-promise-test.js

@@ -20,7 +20,7 @@ class Dog {
   name: string;
   woofs: boolean;
 
-  constructor(name, woofs) {
+  constructor(name: string, woofs: boolean) {
     this.name = name;
     this.woofs = woofs;
   }
@@ -30,7 +30,7 @@ class Cat {
   name: string;
   meows: boolean;
 
-  constructor(name, meows) {
+  constructor(name: string, meows: boolean) {
     this.name = name;
     this.meows = meows;
   }
@@ -39,7 +39,7 @@ class Cat {
 class Human {
   name: string;
 
-  constructor(name) {
+  constructor(name: string) {
     this.name = name;
   }
 }

src/execution/__tests__/abstract-test.js

@@ -20,7 +20,7 @@ class Dog {
   name: string;
   woofs: boolean;
 
-  constructor(name, woofs) {
+  constructor(name: string, woofs: boolean) {
     this.name = name;
     this.woofs = woofs;
   }
@@ -30,7 +30,7 @@ class Cat {
   name: string;
   meows: boolean;
 
-  constructor(name, meows) {
+  constructor(name: string, meows: boolean) {
     this.name = name;
     this.meows = meows;
   }
@@ -39,7 +39,7 @@ class Cat {
 class Human {
   name: string;
 
-  constructor(name) {
+  constructor(name: string) {
     this.name = name;
   }
 }

src/execution/__tests__/directives-test.js

@@ -30,7 +30,7 @@ const rootValue = {
   },
 };
 
-function executeTestQuery(query) {
+function executeTestQuery(query: string) {
   const document = parse(query);
   return execute({ schema, document, rootValue });
 }

src/execution/__tests__/executor-test.js

@@ -103,7 +103,7 @@ describe('Execute: Handles basic execution tasks', () => {
       e: () => 'Egg',
       f: 'Fish',
       // Called only by DataType::pic static resolver
-      pic: (size) => 'Pic of size: ' + size,
+      pic: (size: number) => 'Pic of size: ' + size,
       deep: () => deepData,
       promise: promiseData,
     };
@@ -1006,15 +1006,15 @@ describe('Execute: Handles basic execution tasks', () => {
     class Special {
       value: string;
 
-      constructor(value) {
+      constructor(value: string) {
         this.value = value;
       }
     }
 
     class NotSpecial {
       value: string;
 
-      constructor(value) {
+      constructor(value: string) {
         this.value = value;
       }
     }
@@ -1131,12 +1131,15 @@ describe('Execute: Handles basic execution tasks', () => {
     });
     const document = parse('{ foo }');
 
-    function fieldResolver(_source, _args, _context, info) {
-      // For the purposes of test, just return the name of the field!
-      return info.fieldName;
-    }
+    const result = execute({
+      schema,
+      document,
+      fieldResolver(_source, _args, _context, info) {
+        // For the purposes of test, just return the name of the field!
+        return info.fieldName;
+      },
+    });
 
-    const result = execute({ schema, document, fieldResolver });
     expect(result).to.deep.equal({ data: { foo: 'foo' } });
   });
 
@@ -1168,16 +1171,20 @@ describe('Execute: Handles basic execution tasks', () => {
       types: [fooObject],
     });
 
-    let possibleTypes;
-    function typeResolver(_source, _context, info, abstractType) {
-      // Resolver should be able to figure out all possible types on its own
-      possibleTypes = info.schema.getPossibleTypes(abstractType);
+    const rootValue = { foo: { bar: 'bar' } };
 
-      return 'FooObject';
-    }
+    let possibleTypes;
+    const result = execute({
+      schema,
+      document,
+      rootValue,
+      typeResolver(_source, _context, info, abstractType) {
+        // Resolver should be able to figure out all possible types on its own
+        possibleTypes = info.schema.getPossibleTypes(abstractType);
 
-    const rootValue = { foo: { bar: 'bar' } };
-    const result = execute({ schema, document, rootValue, typeResolver });
+        return 'FooObject';
+      },
+    });
 
     expect(result).to.deep.equal({ data: { foo: { bar: 'bar' } } });
     expect(possibleTypes).to.deep.equal([fooObject]);

src/execution/__tests__/lists-test.js

@@ -11,6 +11,7 @@ import {
   GraphQLList,
   GraphQLNonNull,
   GraphQLObjectType,
+  type GraphQLOutputType,
 } from '../../type/definition';
 
 import { execute } from '../execute';
@@ -27,7 +28,7 @@ const rejected = Promise.reject.bind(Promise);
  * contains a rejection, testData should be a function that returns that
  * rejection so as not to trigger the "unhandled rejection" error watcher.
  */
-function check(testType, testData, expected) {
+function check(testType: GraphQLOutputType, testData: mixed, expected: mixed) {
   return async () => {
     const data = { test: testData };
 
@@ -71,7 +72,7 @@ describe('Execute: Accepts any iterable as list value', () => {
     }),
   );
 
-  function getArgs(...args) {
+  function getArgs(...args: Array<string>) {
     return args;
   }