### Question:
ViewHelper { public static void setImageResource(EfficientCacheView cacheView, int viewId, @DrawableRes int resId) { View view = cacheView.findViewByIdEfficient(viewId); if (view instanceof ImageView) { ((ImageView) view).setImageResource(resId); } }  static void setVisibility(EfficientCacheView cacheView, int viewId, int visibility); static void setBackground(EfficientCacheView cacheView, int viewId, Drawable drawable); static void setBackgroundColor(EfficientCacheView cacheView, int viewId,
            @ColorInt int color); static void setBackgroundResource(EfficientCacheView cacheView, int viewId,
            @DrawableRes int resid); static void setTag(EfficientCacheView cacheView, int viewId, Object tag); static void setTag(EfficientCacheView cacheView, int viewId, int key, Object tag); static void setText(EfficientCacheView cacheView, int viewId, CharSequence text); static void setText(EfficientCacheView cacheView, int viewId, @StringRes int resid); static void setTextColor(EfficientCacheView cacheView, int viewId, @ColorInt int color); static void setTextSize(EfficientCacheView cacheView, int viewId, float size); static void setTextSize(EfficientCacheView cacheView, int viewId, int unit, float size); static void setImageResource(EfficientCacheView cacheView, int viewId,
            @DrawableRes int resId); static void setImageDrawable(EfficientCacheView cacheView, int viewId,
            Drawable drawable); static void setImageUri(EfficientCacheView cacheView, int viewId, @Nullable Uri uri); static void setImageBitmap(EfficientCacheView cacheView, int viewId, Bitmap bm);  }### Answer:
@Test public void testSetImageResource_imageView() throws Exception { int res = android.R.drawable.btn_dialog; ViewHelper.setImageResource(mCacheView, IMAGEVIEW_ID, res); verify(mImageView).setImageResource(res); verifyNoMoreInteractions(mImageView); }
@Test public void testSetImageResource_notImageView() throws Exception { int res = android.R.drawable.btn_dialog; ViewHelper.setImageResource(mCacheView, NULL_VIEW_ID, res); ViewHelper.setImageResource(mCacheView, VIEW_ID, res); ViewHelper.setImageResource(mCacheView, TEXTVIEW_ID, res); verifyZeroInteractions(mTextView, mView); }