[11.x] Add tests to improve test coverage for Arr::whereNotNull (#5…

…1661)

* tests: add some tests for Arr::whereNotNull ( improve test coverage)

* fix code style: using fn instead of function

tests/Support/SupportArrTest.php

@@ -213,10 +213,22 @@ public function testExists()
         $this->assertFalse(Arr::exists(new Collection(['a' => null]), 'b'));
     }
 
-    public function testWhereNotNull()
+    public function testWhereNotNull(): void
     {
         $array = array_values(Arr::whereNotNull([null, 0, false, '', null, []]));
         $this->assertEquals([0, false, '', []], $array);
+
+        $array = array_values(Arr::whereNotNull([1, 2, 3]));
+        $this->assertEquals([1, 2, 3], $array);
+
+        $array = array_values(Arr::whereNotNull([null, null, null]));
+        $this->assertEquals([], $array);
+
+        $array = array_values(Arr::whereNotNull(['a', null, 'b', null, 'c']));
+        $this->assertEquals(['a', 'b', 'c'], $array);
+
+        $array = array_values(Arr::whereNotNull([null, 1, 'string', 0.0, false, [], new stdClass(), fn () => null]));
+        $this->assertEquals([1, 'string', 0.0, false, [], new stdClass(), fn () => null], $array);
     }
 
     public function testFirst()