### Question:
DataTypeConstraintExpressionView implements DataTypeConstraintExpression.View { @Override public void setPlaceholder(final String placeholder) { expression.setAttribute("placeholder", placeholder); } @Inject  DataTypeConstraintExpressionView(final HTMLTextAreaElement expression); @Override void init(final DataTypeConstraintExpression presenter); @Override void setPlaceholder(final String placeholder); @Override String getExpressionValue(); @Override void setExpressionValue(final String value);  }### Answer:
@Test public void testSetPlaceholder() { final String attribute = "placeholder"; final String value = "value"; view.setPlaceholder(value); verify(expression).setAttribute(attribute, value); }