FindCommandParserTest.java: Add test for thrown exception

src/test/java/seedu/address/logic/parser/FindCommandParserTest.java

@@ -3,12 +3,14 @@
 import static seedu.address.logic.Messages.MESSAGE_INVALID_COMMAND_FORMAT;
 import static seedu.address.logic.parser.CommandParserTestUtil.assertParseFailure;
 import static seedu.address.logic.parser.CommandParserTestUtil.assertParseSuccess;
+import static seedu.address.testutil.Assert.assertThrows;
 
 import java.util.List;
 
 import org.junit.jupiter.api.Test;
 
 import seedu.address.logic.commands.FindCommand;
+import seedu.address.logic.parser.exceptions.ParseException;
 import seedu.address.model.person.NameContainsKeywordsPredicate;
 import seedu.address.model.person.RoleContainsKeywordsPredicate;
 
@@ -44,6 +46,27 @@ public void parse_emptyArgumentAfterPrefix_throwsParseException() {
                 String.format(MESSAGE_INVALID_COMMAND_FORMAT, FindCommand.MESSAGE_USAGE));
     }
 
+    @Test
+    public void parse_emptyNameKeyword_throwsParseException() {
+        // Test where the name field is empty
+        String userInput = " n/  r/Developer";  // n/ contains only whitespace
+        assertThrows(ParseException.class, () -> parser.parse(userInput));
+    }
+
+    @Test
+    public void parse_emptyRoleKeyword_throwsParseException() {
+        // Test where the role field is empty
+        String userInput = " n/John Doe r/ ";  // r/ contains only whitespace
+        assertThrows(ParseException.class, () -> parser.parse(userInput));
+    }
+
+    @Test
+    public void parse_emptyNameAndRoleKeywords_throwsParseException() {
+        // Test where both name and role fields are empty
+        String userInput = " n/  r/ ";  // both contain only whitespace
+        assertThrows(ParseException.class, () -> parser.parse(userInput));
+    }
+
     @Test
     public void parse_validArgs_returnsFindCommand() {
         // no leading and trailing whitespaces