### Question:
PropertyExpressionResolver { public boolean containsVariablesPatterns(String str) { return StringUtils.isNotBlank(str) && str.contains(VAR_PREFIX); }  @Nonnull List<NifiProperty> resolvePropertyExpressions(@Nullable final FeedMetadata metadata); List<NifiProperty> resolvePropertyExpressions(@Nullable final FeedMetadata metadata, List<NifiProperty> skip); List<NifiProperty> resolvePropertyExpressions(List<NifiProperty> properties, @Nullable final FeedMetadata metadata); List<NifiProperty> resolvePropertyExpressions(List<NifiProperty> properties, @Nullable final FeedMetadata metadata, List<NifiProperty> skip); Map<String, Object> getStaticConfigProperties(); List<AnnotatedFieldProperty> getMetadataProperties(); List<NifiProperty> resolveStaticProperties(@Nullable final List<NifiProperty> allProperties); boolean containsVariablesPatterns(String str); String resolveVariables(String str, Map<String, String> vars); String replaceAll(String str, String replacement); ResolvedVariables resolveVariables(String str, List<NifiProperty> properties); boolean isConfigProperty(NifiProperty property); static final String configPropertyPrefix; }### Answer:
@Test public void testContainsVariable() { Assert.assertTrue(resolver.containsVariablesPatterns("abc 123 ${var}")); }