Add test for function predicates

src/test/java/org/javarosa/core/model/PredicateCachingTest.java

@@ -220,7 +220,7 @@ public void firstPredicateInMultipleEqPredicatesAreOnlyEvaluatedOnce() throws Ex
  }
 
  @Test
- public void repeatedCompPredicatesWithSameAnswerAreOnlyEvaluatedOnce() throws Exception {
+ public void repeatedCompPredicatesWithSameAbsoluteValueAreOnlyEvaluatedOnce() throws Exception {
  Scenario scenario = Scenario.init("Some form", html(
  head(
  title("Some form"),
@@ -255,6 +255,42 @@ public void repeatedCompPredicatesWithSameAnswerAreOnlyEvaluatedOnce() throws Ex
  assertThat(evaluations, lessThan(4));
  }
 
+ @Test
+ public void repeatedIdempotentFuncPredicatesWithSameAbsoluteValueAreOnlyEvaluatedOnce() throws Exception {
+ Scenario scenario = Scenario.init("Some form", html(
+ head(
+ title("Some form"),
+ model(
+ mainInstance(t("data id=\"some-form\"",
+ t("choice"),
+ t("calculate1"),
+ t("calculate2")
+ )),
+ instance("instance",
+ item("a", "A"),
+ item("b", "B")
+ ),
+ bind("/data/choice").type("string"),
+ bind("/data/calculate1").type("string")
+ .calculate("instance('instance')/root/item[regex(value,/data/choice)]/label"),
+ bind("/data/calculate2").type("string")
+ .calculate("instance('instance')/root/item[regex(value,/data/choice)]/value")
+ )
+ ),
+ body(
+ input("/data/choice")
+ )
+ ));
+
+ int evaluations = Measure.withMeasure(asList("PredicateEvaluation", "IndexEvaluation"), () -> {
+ scenario.answer("/data/choice", "a");
+ scenario.answer("/data/choice", "a");
+ });
+
+ // Check that we do less than size of secondary instance * number of times we answer
+ assertThat(evaluations, lessThan(4));
+ }
+
  /**
  * A form with multiple secondary instances can have expressions with "equivalent" predicates that filter on
  * different sets of children. It's pretty possible to write a bug where these predicates are treated as the same