add: add test cases for FileUtil (#8810)

* add: add test cases for FileUtil

* del: other

* fix: list of

* fix: list of

Co-authored-by: Christina Chen <wenjunc3@uci.edu>

src/test/java/org/jabref/logic/util/io/FileUtilTest.java

@@ -387,4 +387,18 @@ void testIsNotBibFile() throws IOException {
         Path bibFile = Files.createFile(rootDir.resolve("test.pdf"));
         assertFalse(FileUtil.isBibFile(bibFile));
     }
+
+    @Test
+    void testFindinPath() {
+        Optional<Path> resultPath1 = FileUtil.find("existingTestFile.txt", rootDir);
+        assertEquals(resultPath1.get().toString(), existingTestFile.toString());
+    }
+
+    @Test
+    void testFindinListofPath() {
+        List<Path> paths = List.of(existingTestFile, otherExistingTestFile, rootDir);
+        List<Path> resultPaths = List.of(existingTestFile, existingTestFile);
+        List<Path> result = FileUtil.find("existingTestFile.txt", paths);
+        assertEquals(resultPaths, result);
+    }
 }