    @Test
    public void testInjectVariables() {

        VariableAwareFact factMock = mock(VariableAwareFact.class);
        variableStatementResolver.addStatement("a ${b} c", factMock, Fact.class);
        assertEquals(factMock, variableStatementResolver.resolveStatement("a value c", Fact.class));
        Map<String, String> expectedVariables = new HashMap<String, String>();
        expectedVariables.put("b", "value");
        verify(factMock, times(1)).setVariables(expectedVariables);
        verifyNoMoreInteractions(factMock);
    }