Allow AbstractField to override value equality (#8201)

* Allow AbstractField to override value equality

Fixes #8089

1 files changed, 57 insertions, 0 deletions

diff --git a/server/src/test/java/com/vaadin/ui/AbstractFieldTest.java b/server/src/test/java/com/vaadin/ui/AbstractFieldTest.java
index 7f66ca5ed3..8d8d9a6499 100644
--- a/server/src/test/java/com/vaadin/ui/AbstractFieldTest.java
+++ b/server/src/test/java/com/vaadin/ui/AbstractFieldTest.java
@@ -15,6 +15,14 @@ import com.vaadin.server.ClientConnector;
 
 public class AbstractFieldTest extends EasyMockSupport {
 
+    private final class IdentityTextField extends TextField {
+        @Override
+        protected boolean isDifferentValue(String newValue) {
+            // Checks for identity instead of equality
+            return newValue != getValue();
+        }
+    }
+
     class TextField extends AbstractField<String> {
 
         String value = "";
@@ -119,4 +127,53 @@ public class AbstractFieldTest extends EasyMockSupport {
         assertSame("event source connector", source, e.getSource());
         assertEquals("event from user", userOriginated, e.isUserOriginated());
     }
+
+    @Test
+    public void identityField_realChange() {
+        TextField identityField = new IdentityTextField();
+
+        identityField.addValueChangeListener(l);
+
+        // Expect event to both listeners for actual change
+        l.valueChange(EasyMock.capture(capture));
+
+        replayAll();
+
+        identityField.setValue("value");
+
+        verifyAll();
+    }
+
+    @Test
+    public void identityField_onlyIdentityChange() {
+        TextField identityField = new IdentityTextField();
+        identityField.setValue("value");
+
+        identityField.addValueChangeListener(l);
+
+        // Expect event to both listeners for actual change
+        l.valueChange(EasyMock.capture(capture));
+
+        replayAll();
+
+        String sameValueDifferentIdentity = new String("value");
+        identityField.setValue(sameValueDifferentIdentity);
+
+        verifyAll();
+    }
+
+    @Test
+    public void identityField_noChange() {
+        TextField identityField = new IdentityTextField();
+        identityField.setValue("value");
+
+        identityField.addValueChangeListener(l);
+
+        // Expect no event for identical value
+        replayAll();
+
+        identityField.setValue(identityField.getValue());
+
+        verifyAll();
+    }
 }