a few additional tests to cover optional cases

Author: twof

package-lock.json

@@ -63,6 +63,7 @@
     "eslint-plugin-istanbul": "0.1.2",
     "eslint-plugin-node": "11.1.0",
     "eslint-plugin-tsdoc": "0.2.14",
+    "esm": "^3.2.25",
     "mocha": "9.1.0",
     "nyc": "15.1.0",
     "prettier": "2.3.2",

package.json

@@ -255,6 +255,16 @@ describe('Parser', () => {
     ).to.not.throw();
   });
 
+  it('parses optional with alias', () => {
+    expect(() =>
+      parse(`
+      query {
+        requiredField: field?
+      }
+    `),
+    ).to.not.throw();
+  });
+
   it('does not parse aliased field with bang on left of colon', () => {
     expect(() =>
       parse(`
@@ -265,6 +275,16 @@ describe('Parser', () => {
     ).to.throw();
   });
 
+  it('does not parse aliased field with question mark on left of colon', () => {
+    expect(() =>
+      parse(`
+      query {
+        requiredField?: field
+      }
+    `),
+    ).to.throw();
+  });
+
   it('does not parse aliased field with bang on left and right of colon', () => {
     expect(() =>
       parse(`
@@ -275,6 +295,16 @@ describe('Parser', () => {
     ).to.throw();
   });
 
+  it('does not parse aliased field with question mark on left and right of colon', () => {
+    expect(() =>
+      parse(`
+      query {
+        requiredField?: field?
+      }
+    `),
+    ).to.throw();
+  });
+
   it('parses required within fragment', () => {
     expect(() =>
       parse(`
@@ -285,6 +315,16 @@ describe('Parser', () => {
     ).to.not.throw();
   });
 
+  it('parses optional within fragment', () => {
+    expect(() =>
+      parse(`
+      fragment MyFragment on Query {
+        field?
+      }
+    `),
+    ).to.not.throw();
+  });
+
   it('creates ast', () => {
     const result = parse(dedent`
       {