VariablesAreInputTypesRule: add test for ignoring unknown types

src/validation/__tests__/KnownTypeNamesRule-test.ts

@@ -53,7 +53,7 @@ describe('Validate: Known type names', () => {
 
   it('unknown type names are invalid', () => {
     expectErrors(`
-      query Foo($var: JumbledUpLetters) {
+      query Foo($var: [JumbledUpLetters!]!) {
         user(id: 4) {
           name
           pets { ... on Badger { name }, ...PetFields }
@@ -65,7 +65,7 @@ describe('Validate: Known type names', () => {
     `).to.deep.equal([
       {
         message: 'Unknown type "JumbledUpLetters".',
-        locations: [{ line: 2, column: 23 }],
+        locations: [{ line: 2, column: 24 }],
       },
       {
         message: 'Unknown type "Badger".',

src/validation/__tests__/VariablesAreInputTypesRule-test.ts

@@ -13,6 +13,14 @@ function expectValid(queryStr: string) {
 }
 
 describe('Validate: Variables are input types', () => {
+  it('unknown types are ignored', () => {
+    expectValid(`
+      query Foo($a: Unknown, $b: [[Unknown!]]!) {
+        field(a: $a, b: $b)
+      }
+    `);
+  });
+
   it('input types are valid', () => {
     expectValid(`
       query Foo($a: String, $b: [Boolean!]!, $c: ComplexInput) {

src/validation/rules/VariablesAreInputTypesRule.ts

@@ -23,7 +23,7 @@ export function VariablesAreInputTypesRule(
     VariableDefinition(node: VariableDefinitionNode) {
       const type = typeFromAST(context.getSchema(), node.type);
 
-      if (type && !isInputType(type)) {
+      if (type !== undefined && !isInputType(type)) {
         const variableName = node.variable.name.value;
         const typeName = print(node.type);