Fix search: NOT binds more than AND

src/main/antlr4/org/jabref/search/Search.g4

@@ -34,10 +34,11 @@ start:
 // labels are used to refer to parts of the rules in the generated code later on
 // label=actualThingy
 expression:
-    LPAREN expression RPAREN                                  #parenExpression  // example: (author=miller)
-    | left=expression operator=(AND | OR) right=expression    #binaryExpression // example: author = miller and title = test
-    | NOT expression                                          #unaryExpression  // example: not author = miller
-    | comparison                                              #atomExpression
+    LPAREN expression RPAREN                         #parenExpression  // example: (author=miller)
+    | NOT expression                                 #unaryExpression  // example: not author = miller
+    | left=expression operator=AND right=expression  #binaryExpression // example: author = miller and title = test
+    | left=expression operator=OR right=expression   #binaryExpression // example: author = miller or title = test
+    | comparison                                     #atomExpression
     ;
 
 comparison:

src/test/java/org/jabref/model/groups/SearchGroupTest.java

@@ -3,6 +3,7 @@
 import java.util.EnumSet;
 
 import org.jabref.model.entry.BibEntry;
+import org.jabref.model.entry.field.StandardField;
 import org.jabref.model.search.rules.SearchRules;
 
 import org.junit.jupiter.api.Test;
@@ -29,4 +30,24 @@ public void containsDoesNotFindsWordWithInvalidRegularExpression() {
 
         assertFalse(group.contains(entry));
     }
+
+    @Test
+    public void notQueryWorksWithLeftPartOfQuery() {
+        SearchGroup groupToBeClassified = new SearchGroup("to-be-classified", GroupHierarchyType.INDEPENDENT, "NOT(groups=alpha) AND NOT(groups=beta)", EnumSet.noneOf(SearchRules.SearchFlags.class));
+
+        BibEntry alphaEntry = new BibEntry()
+                .withCitationKey("alpha")
+                .withField(StandardField.GROUPS, "alpha");
+        assertFalse(groupToBeClassified.contains(alphaEntry));
+    }
+
+    @Test
+    public void notQueryWorksWithLRightPartOfQuery() {
+        SearchGroup groupToBeClassified = new SearchGroup("to-be-classified", GroupHierarchyType.INDEPENDENT, "NOT(groups=alpha) AND NOT(groups=beta)", EnumSet.noneOf(SearchRules.SearchFlags.class));
+
+        BibEntry betaEntry = new BibEntry()
+                .withCitationKey("beta")
+                .withField(StandardField.GROUPS, "beta");
+        assertFalse(groupToBeClassified.contains(betaEntry));
+    }
 }