!2 An exception is thrown if a field doesn't exist.
!|fitlibrary.spec.SpecifyFixture|
|!-<table><tr><td>fit.specify.ColumnFixtureUnderTest</td></tr>
<tr><td>unknownField</td></tr></table>-!|!-<table><tr><td>fit.specify.ColumnFixtureUnderTest</td></tr>
<tr><td class="error">unknownField<hr/> <span class="fit_label">Could not find field: unknownField.</span></td></tr></table>-!|
