### Question:
RadixTree implements FeedPathStore<T>, Formattable { @Override public synchronized boolean delete(@Nonnull String key, @Nonnull T value) { if (key != null && !key.trim().isEmpty()){ LOG.debug("Delete called for key:{}", key.trim()); return recursiveDelete(key, null, root, value); } return false; } RadixTree(); @Override synchronized int getSize(); @Override synchronized void insert(@Nullable String key, @Nonnull T value); @Override @Nullable synchronized Collection<T> find(@Nonnull String key, FalconRadixUtils.INodeAlgorithm algorithm); @Nullable @Override Collection<T> find(@Nonnull String key); @Override synchronized boolean delete(@Nonnull String key, @Nonnull T value); @Override void formatTo(Formatter formatter, int flags, int width, int precision); @javax.annotation.Nullable List<String> findSuffixChildren(String key, int limit);  }### Answer:
@Test public void testDeleteNonExistent() { Assert.assertFalse(tree.delete("zzz", "zzz")); }
@Test public void testDeleteSubstring() { Assert.assertFalse(tree.delete("ke", "ke")); }
@Test public void testDeleteNonTerminal() { Assert.assertFalse(tree.delete("key", "key")); }
@Test public void testDeleteBlankOrEmptyOrNullString(){ Assert.assertFalse(tree.delete("", "")); Assert.assertFalse(tree.delete(" ", " ")); Assert.assertFalse(tree.delete(null, null)); }