Added explicit error message for Promises passed to getWindowFromNode

Author: Josh Goldberg

src/__tests__/helpers.js

@@ -1,9 +1,24 @@
-import {getDocument, checkContainerType} from '../helpers'
+import {getDocument, getWindowFromNode, checkContainerType} from '../helpers'
 
 test('returns global document if exists', () => {
   expect(getDocument()).toBe(document)
 })
 
+describe('window retrieval throws when given something other than a node', () => {
+  test('Promise as node', () => {
+    expect(() =>
+      getWindowFromNode(new Promise(jest.fn())),
+    ).toThrowErrorMatchingInlineSnapshot(
+      `"It looks like you passed a Promise object instead of a DOM node. Did you use a \\"find\\" search instead of a \\"get\\" or \\"query\\"?"`,
+    )
+  })
+  test('unknown as node', () => {
+    expect(() => getWindowFromNode({})).toThrowErrorMatchingInlineSnapshot(
+      `"Unable to find the \\"window\\" object for the given node. Please file an issue with the code that's causing you to see this error: https://github.com/testing-library/dom-testing-library/issues/new"`,
+    )
+  })
+})
+
 describe('query container validation throws when validation fails', () => {
   test('undefined as container', () => {
     expect(() =>

src/helpers.js

@@ -47,7 +47,6 @@ function getDocument() {
   return window.document
 }
 function getWindowFromNode(node) {
-  // istanbul ignore next I'm not sure what could cause the final else so we'll leave it uncovered.
   if (node.defaultView) {
     // node is document
     return node.defaultView
@@ -57,8 +56,12 @@ function getWindowFromNode(node) {
   } else if (node.window) {
     // node is window
     return node.window
+  } else if (node.then instanceof Function) {
+    throw new Error(
+      `It looks like you passed a Promise object instead of a DOM node. Did you use a "find" search instead of a "get" or "query"?`,
+    )
   } else {
-    // no idea...
+    // The user passed something unusual to a calling function
     throw new Error(
       `Unable to find the "window" object for the given node. Please file an issue with the code that's causing you to see this error: https://github.com/testing-library/dom-testing-library/issues/new`,
     )