### Question:
ColumnStore implements ColumnIterable { public boolean hasColumn(String key) { checkNonNullObject(key); lock(); try { return idMap.containsKey(key.toLowerCase()); } finally { unlock(); } } ColumnStore(Class<T> elementType, boolean indexed);  ColumnStore(GraphStore graphStore, Class<T> elementType, boolean indexed); void addColumn(final Column column); void removeColumn(final Column column); void removeColumn(final String key); int getColumnIndex(final String key); Column getColumnByIndex(final int index); Column getColumn(final String key); boolean hasColumn(String key); @Override Iterator<Column> iterator(); @Override ColumnImpl[] toArray(); @Override List<Column> toList(); @Override void doBreak(); Set<String> getColumnKeys(); void clear(); int size(); boolean deepEquals(ColumnStore<T> obj); int deepHashCode();  }### Answer:
@Test public void testHasColumn() { ColumnStore<Node> store = new ColumnStore(Node.class, false); ColumnImpl col = new ColumnImpl("0", Integer.class, null, null, Origin.DATA, false, false); store.addColumn(col); Assert.assertTrue(store.hasColumn(col.getId())); Assert.assertFalse(store.hasColumn("")); Assert.assertFalse(store.hasColumn("A")); }