WIP: Fix remaining unit test failures

packages/mdc-textfield/foundation.ts

@@ -462,7 +462,11 @@ class MDCTextFieldFoundation extends MDCFoundation<MDCTextFieldAdapter> {
    * @return The native text input from the host environment, or a dummy if none exists.
    */
   private getNativeInput_(): HTMLInputElement | NativeInputType {
-    return this.adapter_.getNativeInput() || {
+    // adapter_ can be undefined in foundation unit tests. This happens when testdouble is creating a mock object and
+    // invokes the shouldShake/shouldFloat getters (which in turn call getValue(), which calls this method) before
+    // init() has been called in the MDCTextField constructor.
+    const nativeInput = this.adapter_ ? this.adapter_.getNativeInput() : null;
+    return nativeInput || {
       disabled: false,
       maxLength: -1,
       type: 'input',

test/unit/mdc-textfield/foundation.test.js

@@ -56,16 +56,16 @@ test('defaultAdapter returns a complete adapter implementation', () => {
   ]);
 });
 
-const setupTest = () => {
+const setupTest = ({characterCounter = false} = {}) => {
   const mockAdapter = td.object(MDCTextFieldFoundation.defaultAdapter);
   const helperText = td.object({
     setContent: () => {},
     showToScreenReader: () => {},
     setValidity: () => {},
   });
-  const characterCounter = td.object({
+  characterCounter = characterCounter === true ? td.object({
     setCounterValue: () => {},
-  });
+  }) : undefined;
   const leadingIcon = td.object({
     setDisabled: () => {},
     setAriaLabel: () => {},
@@ -866,7 +866,7 @@ test('#handleInput activates focus state', () => {
 });
 
 test('#handleInput updates character counter on text input', () => {
-  const {foundation, mockAdapter, characterCounter} = setupTest();
+  const {foundation, mockAdapter, characterCounter} = setupTest({characterCounter: true});
 
   const nativeInput = {
     type: 'text',
@@ -884,7 +884,7 @@ test('#handleInput updates character counter on text input', () => {
 
 
 test('#handleInput throws error when maxLength HTML attribute is not found in input element', () => {
-  const {foundation, mockAdapter} = setupTest();
+  const {foundation, mockAdapter} = setupTest({characterCounter: true});
 
   const nativeInput = {
     type: 'text',
@@ -901,7 +901,7 @@ test('#handleInput throws error when maxLength HTML attribute is not found in in
 
 test('#handleValidationAttributeChange sets character counter when maxlength attribute value is changed in input ' +
     'element', () => {
-  const {foundation, mockAdapter, characterCounter} = setupTest();
+  const {foundation, mockAdapter, characterCounter} = setupTest({characterCounter: true});
 
   const nativeInput = {
     type: 'text',