diff --git a/src/org/opendatakit/validate/FormValidator.java b/src/org/opendatakit/validate/FormValidator.java
index 1421253..1cb208d 100644
--- a/src/org/opendatakit/validate/FormValidator.java
+++ b/src/org/opendatakit/validate/FormValidator.java
@@ -493,6 +493,30 @@ public Object eval(Object[] args, EvaluationContext ec) {
                         return args[0];
                     }});
 
+                fd.getEvaluationContext().addFunctionHandler(new IFunctionHandler() {
+
+                    public String getName() {
+                        return "intersects";
+                    }
+
+                    public List<Class[]> getPrototypes() {
+                        return new ArrayList<>();
+                    }
+
+                    public boolean rawArgs() {
+                        return true;
+                    }
+
+                    public boolean realTime() {
+                        return false;
+                    }
+
+                    public Object eval(Object[] args, EvaluationContext ec) {
+                        // stub for validation
+                        return true;
+                    }
+                });
+
                 // check for runtime errors
                 fd.initialize(true, new InstanceInitializationFactory());
 
diff --git a/src/test/java/org/opendatakit/validate/CollectFunctionHandlerTest.java b/src/test/java/org/opendatakit/validate/CollectFunctionHandlerTest.java
new file mode 100644
index 0000000..e79986d
--- /dev/null
+++ b/src/test/java/org/opendatakit/validate/CollectFunctionHandlerTest.java
@@ -0,0 +1,23 @@
+package org.opendatakit.validate;
+
+import org.junit.Test;
+
+import java.net.URISyntaxException;
+import java.nio.file.Path;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.isEmptyString;
+
+public class CollectFunctionHandlerTest {
+
+    @Test
+    public void acceptsIntersects() throws URISyntaxException {
+        final Path path = TestUtils.getPathOf("intersects_function.xml");
+        final FormValidator validator = new FormValidator();
+
+        Output output = Output.runAndGet(() -> validator.validate(path.toString()));
+        assertThat(output.getErr(), isEmptyString());
+        assertThat(output.getStd(), containsString("Xform is valid"));
+    }
+}
diff --git a/src/test/java/org/opendatakit/validate/Output.java b/src/test/java/org/opendatakit/validate/Output.java
new file mode 100644
index 0000000..367a48b
--- /dev/null
+++ b/src/test/java/org/opendatakit/validate/Output.java
@@ -0,0 +1,48 @@
+package org.opendatakit.validate;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+public class Output {
+    private final String std;
+    private final String err;
+
+    Output(String std, String err) {
+        this.std = std;
+        this.err = err;
+    }
+
+    static Output runAndGet(Runnable runnable) {
+        PrintStream outBackup = System.out;
+        ByteArrayOutputStream stdBaos = new ByteArrayOutputStream();
+        PrintStream stdPs = new PrintStream(stdBaos);
+        System.setOut(stdPs);
+
+        PrintStream errBackup = System.err;
+        ByteArrayOutputStream errBaos = new ByteArrayOutputStream();
+        PrintStream errPs = new PrintStream(errBaos);
+        System.setErr(errPs);
+
+        runnable.run();
+
+        stdPs.flush();
+        String std = stdBaos.toString();
+        System.setOut(outBackup);
+        System.out.print(std);
+
+        errPs.flush();
+        String err = errBaos.toString();
+        System.setErr(errBackup);
+        System.err.print(err);
+
+        return new Output(std, err);
+    }
+
+    public String getStd() {
+        return std;
+    }
+
+    public String getErr() {
+        return err;
+    }
+}
diff --git a/src/test/java/org/opendatakit/validate/TestUtils.java b/src/test/java/org/opendatakit/validate/TestUtils.java
new file mode 100644
index 0000000..ab3e5f0
--- /dev/null
+++ b/src/test/java/org/opendatakit/validate/TestUtils.java
@@ -0,0 +1,11 @@
+package org.opendatakit.validate;
+
+import java.net.URISyntaxException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+public class TestUtils {
+    public static Path getPathOf(String filename) throws URISyntaxException {
+        return Paths.get(ValidateExternalSecondaryInstancesTest.class.getResource(filename.startsWith("/") ? filename : "/" + filename).toURI());
+    }
+}
diff --git a/src/test/java/org/opendatakit/validate/ValidateExternalSecondaryInstancesTest.java b/src/test/java/org/opendatakit/validate/ValidateExternalSecondaryInstancesTest.java
index c19b09e..47c6d00 100644
--- a/src/test/java/org/opendatakit/validate/ValidateExternalSecondaryInstancesTest.java
+++ b/src/test/java/org/opendatakit/validate/ValidateExternalSecondaryInstancesTest.java
@@ -3,12 +3,10 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.isEmptyString;
+import static org.opendatakit.validate.TestUtils.getPathOf;
 
-import java.io.ByteArrayOutputStream;
-import java.io.PrintStream;
 import java.net.URISyntaxException;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import org.junit.Test;
 
 public class ValidateExternalSecondaryInstancesTest {
@@ -18,8 +16,8 @@ public void supportsXlsformsDefaultValueAndLabelRefs_inItemsets_usingXMLExternal
         final FormValidator validator = new FormValidator();
 
         Output output = Output.runAndGet(() -> validator.validate(path.toString()));
-        assertThat(output.err, isEmptyString());
-        assertThat(output.std, containsString("Xform is valid"));
+        assertThat(output.getErr(), isEmptyString());
+        assertThat(output.getStd(), containsString("Xform is valid"));
     }
 
     @Test
@@ -28,8 +26,8 @@ public void supportsXlsformsDefaultValueAndLabelRefs_inItemsets_usingCsvSecondar
         final FormValidator validator = new FormValidator();
 
         Output output = Output.runAndGet(() -> validator.validate(path.toString()));
-        assertThat(output.err, isEmptyString());
-        assertThat(output.std, containsString("Xform is valid"));
+        assertThat(output.getErr(), isEmptyString());
+        assertThat(output.getStd(), containsString("Xform is valid"));
     }
 
     @Test
@@ -38,48 +36,7 @@ public void supportsCustomValueAndLabelRefs_inItemsets_usingExternalSecondaryIns
         final FormValidator validator = new FormValidator();
 
         Output output = Output.runAndGet(() -> validator.validate(path.toString()));
-        assertThat(output.err, isEmptyString());
-        assertThat(output.std, containsString("Xform is valid"));
+        assertThat(output.getErr(), isEmptyString());
+        assertThat(output.getStd(), containsString("Xform is valid"));
     }
-
-    private Path getPathOf(String filename) throws URISyntaxException {
-        return Paths.get(ValidateExternalSecondaryInstancesTest.class.getResource(filename.startsWith("/") ? filename : "/" + filename).toURI());
-    }
-
-    static class Output {
-        private final String std;
-        private final String err;
-
-        Output(String std, String err) {
-            this.std = std;
-            this.err = err;
-        }
-
-        static Output runAndGet(Runnable runnable) {
-            PrintStream outBackup = System.out;
-            ByteArrayOutputStream stdBaos = new ByteArrayOutputStream();
-            PrintStream stdPs = new PrintStream(stdBaos);
-            System.setOut(stdPs);
-
-            PrintStream errBackup = System.err;
-            ByteArrayOutputStream errBaos = new ByteArrayOutputStream();
-            PrintStream errPs = new PrintStream(errBaos);
-            System.setErr(errPs);
-
-            runnable.run();
-
-            stdPs.flush();
-            String std = stdBaos.toString();
-            System.setOut(outBackup);
-            System.out.print(std);
-
-            errPs.flush();
-            String err = errBaos.toString();
-            System.setErr(errBackup);
-            System.err.print(err);
-
-            return new Output(std, err);
-        }
-    }
-
 }
diff --git a/src/test/resources/intersects_function.xml b/src/test/resources/intersects_function.xml
new file mode 100644
index 0000000..c8d65ae
--- /dev/null
+++ b/src/test/resources/intersects_function.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0"?>
+<h:html xmlns="http://www.w3.org/2002/xforms" xmlns:odk="http://www.opendatakit.org/xforms"
+        xmlns:jr="http://openrosa.org/javarosa" xmlns:h="http://www.w3.org/1999/xhtml"
+        xmlns:orx="http://openrosa.org/xforms">
+    <h:head>
+        <h:title>Form with intersects</h:title>
+        <model>
+            <instance>
+                <data id="intersects">
+                    <q1/>
+                    <calc/>
+                </data>
+            </instance>
+            <bind nodeset="/data/calc" calculate="if(intersects(/data/q1), 'y', 'n')" type="string"/>
+        </model>
+    </h:head>
+    <h:body>
+        <input ref="/data/q1"/>
+    </h:body>
+</h:html>