JosmTextField: setHint now properly returns the old hint

See #21319/r18221. This additionally adds a non-regression test.

git-svn-id: https://josm.openstreetmap.de/svn/trunk@18538 0c6e7542-c601-0410-84e7-c038aed88b3b

Author: taylor.smock

src/org/openstreetmap/josm/gui/widgets/JosmTextField.java

@@ -180,7 +180,7 @@ public final String getHint() {
      * @since 18221 (signature)
      */
     public String setHint(String hint) {
-        String old = hint;
+        String old = this.hint;
         this.hint = hint;
         return old;
     }

test/unit/org/openstreetmap/josm/gui/widgets/JosmTextFieldTest.java

@@ -0,0 +1,22 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.widgets;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+import org.openstreetmap.josm.testutils.annotations.BasicPreferences;
+
+/**
+ * Test class for {@link JosmTextField}
+ */
+@BasicPreferences
+class JosmTextFieldTest {
+    @Test
+    void testSetHint() {
+        JosmTextField josmTextField = new JosmTextField();
+        josmTextField.setHint("some hint");
+        assertEquals("some hint", josmTextField.getHint());
+        assertEquals("some hint", josmTextField.setHint("new hint"));
+        assertEquals("new hint", josmTextField.getHint());
+    }
+}