add unit test to generateInstitutionKey

src/main/java/org/jabref/logic/citationkeypattern/BracketedPattern.java

@@ -36,6 +36,7 @@
 import org.jabref.model.strings.LatexToUnicodeAdapter;
 import org.jabref.model.strings.StringUtil;
 
+import com.google.common.annotations.VisibleForTesting;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -1218,14 +1219,14 @@ protected static List<String> parseFieldAndModifiers(String arg) {
      *         <li>null if content is null</li>
      *         </ul>
      */
-    private static String generateInstitutionKey(String content) {
+     @VisibleForTesting
+     static String generateInstitutionKey(String content) {
         if (content == null) {
             return null;
         }
         if (content.isBlank()) {
             return "";
         }
-
         Matcher matcher = INLINE_ABBREVIATION.matcher(content);
         if (matcher.find()) {
             return LatexToUnicodeAdapter.format(matcher.group());
@@ -1309,8 +1310,7 @@ private static String generateInstitutionKey(String content) {
         // Putting parts together.
         return (university == null ? Objects.toString(rest, "") : university)
                 + (school == null ? "" : school)
-                + ((department == null)
-                || ((school != null) && department.equals(school)) ? "" : department);
+                + ((department == null) || (department.equals(school)) ? "" : department);
     }
 
     /**

src/test/java/org/jabref/logic/citationkeypattern/BracketedPatternTest.java

@@ -20,6 +20,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
@@ -734,4 +735,31 @@ void editorFieldMarkers(String expectedCitationKey, String pattern, String edito
         BracketedPattern bracketedPattern = new BracketedPattern(pattern);
         assertEquals(expectedCitationKey, bracketedPattern.expand(bibEntry));
     }
+
+    @ParameterizedTest
+    @CsvSource({
+        "'', ''",
+        "The Attributed Graph Grammar System ({AGG}),AGG",
+        "'The University of Science',UniScience",
+        "'School of Business, Department of Management',BM",
+        "'Graph Systems Research Group',GSRG",
+        "'The Great Institute, 123 Main Street, Springfield',GreatInstitute",
+        "'Invalid {\\Unicode}',Invalid",
+        "'School of Electrical Engineering ({SEE}), Department of Computer Science',SEE",
+        "'{The Attributed Graph Grammar System ({AGG})}',AGG",
+        "'{The Attributed Graph Grammar System}',AGGS",
+        "'{University of Example, Department of Computer Science, Some Address}',UniExampleCS",
+        "'{Example School of Engineering, Department of Computer Science, Some Address}',SomeAddressEECS",
+        "'{Example Institute, Computer Science Department, Some Address}',ExampleInstituteCS",
+        "'{Short Part, Some Address}',ShortPart",
+        "'{Example with Several Tokens, Some Address}',EST"})
+
+    void generateInstitutionKeyTest(String input, String expected) {
+        assertEquals(expected, BracketedPattern.generateInstitutionKey(input));
+    }
+
+    @Test
+    void generateInstitutionKeyNullTest() {
+        assertNull(BracketedPattern.generateInstitutionKey(null));
+    }
 }