chore(typescript): add tests for null and false children

test/glamorous.test.tsx

@@ -564,3 +564,37 @@ const BuiltinStyledWithMultipleChild: JSX.Element = (
     <glamorous.Span>world!</glamorous.Span>
   </glamorous.Div>
 );
+
+const CustomStatelessComponent: React.SFC<{}> = (_props) => <div />
+class CustomClassComponent extends React.Component<{}, {}> {
+  render() {
+    return null
+  }
+}
+const CustomGlamorousComponent = glamorous.div()
+const CustomGlamorousComponent2 = glamorous('div')()
+const CustomGlamorousComponent3 = glamorous(CustomGlamorousComponent)()
+const BuiltinStyledComponentChildren: JSX.Element = (
+  <glamorous.Div height={18}>
+    <CustomStatelessComponent />
+    <CustomClassComponent />
+    <CustomGlamorousComponent />
+    <CustomGlamorousComponent2 />
+    <CustomGlamorousComponent3 />
+  </glamorous.Div>
+)
+const BuiltinStyledWithPrimitivesChildren: JSX.Element = (
+  <glamorous.Div color='red'>
+    {null}
+    {false}
+    {true}
+    {undefined}
+    {5}
+  </glamorous.Div>
+);
+
+const BuiltinStyledWithFragment: JSX.Element = (
+  <glamorous.Div color='red'>
+    <React.Fragment />
+  </glamorous.Div>
+);